Wide receivers have been dominating the NFL’s 2013 free-agency period, and Wednesday delivered perhaps the most stunning move when Wes Welker signed with the Denver Broncos for just two years and $12 million, according to ESPN.

From Tom Brady to Peyton Manning, Welker sure lives a charmed life, getting to play in two of the most efficient offensive systems in NFL history.

But this comes after his tumultuous attempts at a long-term deal with the Patriots in the last two offseasons. The final offer from New England was said to be for only two years and $10 million.

Now Welker can play behind outside receivers Demaryius Thomas and Eric Decker without having to be the most-targeted option, like he was in New England.

Since Bill Belichick is not allowed to feature an offense with six tight ends, something had to be done quickly. New England responded by inking Welker clone Danny Amendola from the Rams to a five-year contract worth $31 million.

Did Denver just get the steal of free agency and cripple a rival in the process? Did the Patriots make a huge mistake by playing hardball? How will Welker fare in Denver?

Things are heating up, so let’s get down to it with the stark reminder that we still have almost six months to wait until real games are played.  

Welker’s Road to Denver

With some reporting Denver getting the “best slot receiver in the game,” it does make one recall just how things have reached this point for Welker. Even when a player finds a perfect home, rarely does he finish his career there in this business.

The first time I ever heard of Welker was in a December 2004 game between the Patriots and Dolphins on Monday Night Football. He returned a punt 71 yards down to the 2-yard line, and the underdog Dolphins scored a touchdown on the next play.

Miami went on to win that night, becoming the first two-win team in NFL history to beat a 12-win team. But Welker did not make his first reception in the NFL until 2005, and it was again a home game against the Patriots when he caught my attention with a 47-yard catch late in the game.

Those big efforts against New England really paid off, because after catching 67.0 percent of his passes from Miami’s dreadful quarterbacks in 2006, the Patriots traded their second and seventh-round picks in 2007 to acquire Welker.

Still the underdog at that point, many scoffed at the trade for a player with 96 receptions and one touchdown.

But the Patriots had innovation in mind with their 2007 offensive overhaul, and pairing Welker with deep threat Randy Moss was the perfect duo to complement each other. Moss set the individual records, but it was Welker’s dominance underneath that paced the offense, setting numerous records and nearly capping off a perfect season.

The Patriots showed teams how to run the shotgun-spread offense at the NFL level, and Welker’s screens, curls, slants and other short routes went on to produce five seasons with at least 111 receptions. That is a NFL record.

Even after Moss was gone and the Patriots evolved around their two tight ends, Welker improved, finishing the last two seasons with his most yards: 1,569 yards in 2011 and 1,354 yards in 2012.

Never has a NFL offense used a slot receiver as its No. 1 before the Patriots carved out the unique role to specifically to take advantage of Welker’s strengths.

Since 1990, no wide receiver (minimum 400 receptions) has a higher catch rate (71.18 percent) or yards-after-catch percentage (52.19 percent) than Welker.

You can see his catch rate has fallen a little the last three seasons as he has had more issues with drops, but 69.2 percent would still likely be the best percentage in NFL history. Welker is also converting a higher rate of his catches into first downs over the last two years.

While many would label Welker as a system receiver, there is no denying his consistent production and durability. There is really nothing like it in NFL history.

Yet with some concerns over age (Welker will be 32 this year) and dropped passes, the Patriots seemed content to move on. This comes despite the fact that Welker’s value is higher in New England than it is anywhere else in the league.

So how can Welker thrive without New England’s system?

The good news for him is that Denver may be second on that list of teams who could maximize Welker’s ability.

Welker Can Rebrand Himself in Denver

The Patriots practically rebranded the “slot receiver” for the league with Welker’s instant success.

But it has also done some harm in that people now think of slot receivers as being small guys who catch a lot of screens and do not get deep. Oh, and whether you choose to notice it or not, pointing out when these players are white is also very common.

If you are a white wide receiver, there is a 90 percent chance you have been compared to Welker since 2007. That is not a scientific figure, it just sounds like one.

No matter what skin color they have, slot receivers are not limited to just short routes. Victor Cruz plays in the slot and he has quickly ascended to being one of the greatest deep threats in the game with the Giants.

Any receiver can line up in the slot on any given play, and that is increasingly including big, athletic tight ends.

As mentioned already, Welker’s usage in New England was extremely unique. That role will be expanded in Denver, which is still the next best destination for Welker to land. Peyton Manning’s offense may not be the most complex in the league, but none have been run at such a consistently high level for so many years.

If Thomas and Decker, receivers who had previous experience in run-heavy offenses like Georgia Tech and whatever you want to call Tim Tebow’s shtick, can immediately figure it out with huge seasons, Welker will be fine.

You can already expect “11” personnel with Welker in the slot as the base offense. While he will still primarily stay within 10 yards and catch his share of slip screens, Manning will use him down the seam and on the intermediate and deep routes that were largely missing in New England.

That has been the flaw in New England’s limited passing attack. It was exposed in Super Bowl XLVI when Brady was off on a vertical pass that Welker could not catch late in the fourth quarter.

In their career together, Brady connected with Welker for just 15 completions on passes thrown 21-plus yards. That is a very low number for someone who averages over seven catches a game.

That includes four deep catches last year on 175 regular-season targets (2.29 percent). Even the ancient Brandon Stokley had three such catches on 58 targets (5.17 percent) last season.

Expect a boost in Welker’s vertical success this year. It starts with the quarterback.

Peyton Manning Has Owned Slot Machines for Years

Welker will have more opportunities for big pass plays in Denver, because in this offense any receiver can go deep at any given time, and that most certainly includes the slot receiver.

This is like giving Manning another Stokley or Austin Collie, but the difference is Welker has proven he can stay healthy for a full season.

Again, those three receivers will likely be compared because they are white and play in the slot, but there are still physical differences. Collie is listed at 6’1”, Stokley is 5’11” and Welker is 5’9”. When you keep dropping two inches, you may see a decline in how often the quarterback uses them deep.

But Welker will be used deep regardless, because that is how Manning plays the position.

Welker directly replaces Stokley, who was going to be 37 this season. Have no worries on Manning being able to use the trio of Thomas, Decker and Welker together. In 2004 Manning had a record-breaking season and was able to satisfy three Colts receivers with over 1,000 yards and double-digit touchdowns each.

Stokley was that third guy, working out of the slot, but still making plays down the field. Manning’s 49th touchdown pass of the season was a perfectly-anticipated throw to the end zone for a 21-yard touchdown.

That is a memorable touchdown for Stokley, but a better play came nearly eight years later and also against the Chargers. It was Monday Night Football last year when Stokley caught this 21-yard touchdown that proved to be the game-winning score:

Stokley works from the right slot to the outside, and Manning gives him a chance to fight for the ball and a great catch. This is not the kind of play you saw in New England with Welker as the intended receiver.

Would Manning throw such a pass to the shorter Welker? History suggests he will.  

Going back to Indianapolis, after Stokley was setback by injuries, he was released by the Colts after 2006. Manning paired up with Collie in 2009. His highlight game was the AFC Championship against the Jets, featuring this 46-yard strike between two defenders from Manning after Collie simply ran a go-route:

Collie followed that up with a touchdown on the next play. But that deep pass also remains one of the all-time throws in Manning’s career.

The 2010 season will not go down as one of Manning’s best statistically, but it did start historically well. Collie was a big reason for that. He had a 171-yard game in Denver in Week 3, including more success on deep passes.

In 2010 Manning completed 58-of-71 passes thrown to Collie (81.7 percent). It would have been an All-Pro season for Collie if not for so many injuries. Manning’s seam passes are not only deadly because of the accuracy, but the receivers can endure a brutal hit on them. Keep your head on a swivel, Wes.

After missing 2011, Manning returned in Denver last year with his old teammate, Stokley, and again the slot mastery continued.  Even in his old age, Stokley still caught 45-of-58 targets last season. That is a scintillating catch rate of 77.6 percent, or slightly better than any of Welker’s seasons (albeit in a much smaller sample size). Stokley even caught 13-of-19 targets (68.4 percent) thrown at least 11 yards down the field.

That means in his last two seasons, Manning has completed 103-of-126 passes (79.8 percent) to his primary slot receiver. The 2010 season for Collie and 2012 season for Stokley are the two-highest catch rates in any season by a wide receiver since 2000 (minimum 40 targets).

Now, how good can the numbers be to Welker in this offense?

Welker certainly offers more speed than Stokley, and his vertical game may simply be an untapped talent Denver can utilize more than the Patriots did. In last year’s AFC Championship, Welker came out of the left slot and used a ridiculous double move to fake out Baltimore’s Corey Graham for this 36-yard reception:

Playing in Denver with great outside talent, along with Manning’s pre-snap reads and use of tempo with the no-huddle offense, there is no reason Welker cannot find favorable matchups on plays like this.

But Welker’s bread-and-butter plays will still come underneath the coverage, which Manning will oblige him with often. Welker will become a big weapon on third and manageable.

According to Pro-Football-Reference, Denver was already No. 3 in 2012 at converting third down when needing 1-7 yards (56.0 percent). The Patriots were the best in the league at 59.7 percent. Welker had 15 of their first downs on just 19 targets.

Welker has 95 catches in those third-down situations since 2007. Only Tony Gonzalez (96) has more. He is a weapon to have in that situation. Even if the defense knows that, Denver still has Thomas and Decker, who are not going away this season.

With all of that talent, Welker may not crack 100 receptions or 1,200 yards again. After the season Trindon Holliday had, he may not have to make a single return this season, either.

But make no mistake about it. Welker makes Denver a more efficient offense and puts them in better position to win it all. He will certainly be worth every penny spent.

It is still hard to believe John Elway only had to spend as many pennies as he did to make this happen.

Wes Welker vs. Danny Amendola

It is possible Welker will be a bigger loss for New England than it is a gain for Denver. With that reception-eating receiver gone in Brady’s offense, how can the Patriots possibly replace that much production?

Well, if the Patriots can make a converted quarterback like Julian Edelman look like Welker, then they can do the same with Amendola, who has practically been his understudy.

Amendola plays the same style, has been a return specialist, has a very similar build and even comes from the Texas Tech offense coached by Mike Leach that Welker played in. Amendola is also four years younger than Welker, turning 28 in November.

But what Amendola does not possess is durability. He has only played in 12 games the last two seasons combined after suffering multiple injuries. Like Welker, he plays the game with a strong, physical nature despite being smaller than most of the defenders.

However, Welker has handled a much larger workload with incredible durability, popping back up after countless big shots from safeties and others. Pittsburgh’s Ryan Clark was moments away from a gridiron homicide charge after a hit in 2008.

Welker did tear his ACL on a non-contact play (Patriot-hitman Bernard Pollard was in the vicinity) in Week 17 of the 2009 season, but other than that, he has been available to his team almost every week.

Amendola also averages just 8.81 yards per reception in his career, which is a disgustingly-low average. Though he has shown some ability to get deep, he gives new meaning to being a dink-and-dunk receiver.

While clearly not as polished as Welker, playing in the New England offense with Brady should enhance Amendola’s game the way it did for Welker when he came from the Dolphins in 2007.

Expecting him to take on 150-plus targets in the manner that Welker did may be asking a bit too much from the Patriots, especially in 2013. Clearly wanting to have a receiver of this nature in their offense, the Patriots are basically paying for the younger Amendola without the cost (and benefit) of health insurance, which you get from Welker.

Edelman would have been an even cheaper option to replace Welker, but Amendola it is. The Patriots will likely fit Amendola under a consistent, limited role the way they did Welker, because they believe this system will maximize his strengths.

Though he would seem like a lock for at least 80 receptions this year, Amendola’s ability to stay healthy after weekly beatings will be the biggest factor in determining whether he is a success.

After not being able to agree with Welker, Amendola was the best option New England had in the slot.

Signings Could Be Monumental in Completing Legacies for Manning and Brady

The 2013 regular-season meeting in New England between the Patriots and Broncos just got even more interesting after the Welker signing. It should be a prime-time affair rather than CBS giving Phil Simms the opportunity to call New England’s slot receiver four different names.

Both teams have major championship aspirations, and Wednesday’s events could impact not only the 2013 prospects, but the remainder of the time-dwindling careers for Manning and Brady as they try to win another Super Bowl.

No quarterback has ever won a Super Bowl after a gap of more than six seasons (Roger Staubach won in 1971 and 1977). This will be the seventh and ninth season for Manning and Brady, respectively.

If Amendola can replicate Welker to a tee, the Patriots basically replaced him with a younger version for the remainder of Brady’s career. I still think they need to move away from an overreliance on a slot receiver, but apparently it is vital for their success.

Denver is getting a great deal on a durable receiver who only needs to be the third-best option most of the time. Welker may not exceed 100 catches again, but he no longer has to in this offense.

Only time will tell, but right now it is hard not to say the Broncos have done the better job of putting themselves in position for a championship. The Patriots played hardball with Welker and have gone with a risky replacement.

If Welker helps Denver win a championship, and Amendola proves to be just a one-armed bandit (as in another injury), then that difference of $2 million will look awfully petty for the Patriots.

You have to put good money in a slot machine to win big. Some expected the money saved from the restructuring of Brady’s contract would be used on Welker, but instead it’s the AFC-rival Broncos coming away with another weapon.

Hard to believe Welker, that little undrafted receiver out of Texas Tech, will now be known as the receiver who played with the two best quarterbacks of his era. Harder to believe how much of an impact he can have on how their careers finish.

Scott Kacsmar writes for Cold, Hard Football Facts, NBC Sports, Colts Authority, and contributes data to Pro-Football-Reference.com and NFL Network. You can visit his blog for a complete writing archive, and can follow him on Twitter at @CaptainComeback.