Summer is a hopeful time of year for NFL head coaches. No one has to worry about the temperature of their chair or getting put on blast on the radio.

Not yet, anyway.

Soon enough, the pressure will start to build on coaches. Whether it's Hue Jackson in Cleveland, Marvin Lewis in Cincinnati or maybe even John Harbaugh in Baltimore, plenty of coaches are in the crosshairs in 2018.

Win more games or suffer the consequences.

One coach's professional catastrophe is another's opportunity, whether it's a long-time assistant, a young up-and-comer or a hot name from the collegiate ranks.

As seats start heating up, expect the following names to be bandied about as potential replacements for the next round of head coaches to be fired.

Josh McDaniels

Even after he backed out on the Indianapolis Colts at the last possible second, there's little doubt that Josh McDaniels will come up as a target to fill head coaching vacancies a year from now.

Since 2012, McDaniels has been Bill Belichick's offensive coordinator in New England, helming an offense that has guided the Pats to six straight AFC Championship Games, three Super Bowls and two Lombardi Trophies.

Having Tom Brady helps, but still.

However, the 42-year-old also has a few strikes working against him. 

The first is his disastrous 11-17 first stint as a head coach in Denver in 2009 and 2010. McDaniels clashed with quarterback Jay Cutler and wide receiver Brandon Marshall, both of whom were shipped out of town.

The bigger issue is what happened in Indy this year. After being announced as the Colts head coach and with a press conference scheduled to introduce him, McDaniels backed out after meeting with Belichick and Patriots owner Robert Kraft.

It wasn't a good look, even though McDaniels had only verbally agreed to take the job. In fact, McDaniels' agent fired him as a client after things fell apart.

Many teams may be leery of pursuing McDaniels after what happened in Indianapolis, and he may have his sights set on succeeding Belichick. But all it takes is one team to say yes.

Well, and McDaniels. For real this time.

John DeFilippo

Minnesota Vikings offensive coordinator John DeFilippo knows all about the ups and downs of life as an NFL coach.

From 2005-09, DeFilippo served as a quality control and quarterbacks coach for the New York Giants, Oakland Raiders and New York Jets. Then came a two-year absence from the NFL before he returned to the NFL ranks to coach the quarterbacks in Oakland again.

DeFilippo's first big break came in 2015, when Mike Pettine named him the offensive coordinator of the Cleveland Browns after Kyle Shanahan left. But DeFilippo's good fortune didn't last long, as the Browns finished that year 3-13 and 25th in the NFL in total offense, which resulted in both DeFilippo and Pettine being fired.

That may have been a blessing in disguise. When Doug Pederson was hired to coach the Philadelphia Eagles, he brought in DeFilippo as his quarterbacks coach, tasking him with grooming the young quarterback the Eagles moved up to select second overall in the 2016 draft.

Not only did DeFilippo do great work with Carson Wentz, but when the MVP front-runner tore his ACL last December, veteran backup Nick Foles led Philly all the way to the first Super Bowl win in franchise history.

That magical season put DeFilippo squarely on the map of potential head coaching candidates, although the 2018 carousel spun without him landing a big chair. But when Pat Shurmur left Minnesota to take the head job with the New York Giants, DeFilippo took over as the offensive coordinator for a Vikings team as stacked with skill-position talent as any in the NFL.

If DeFilippo and the Vikings have a good year—and why wouldn't they?—it's only a matter of time before he gets his shot.

Teryl Austin

Teryl Austin has been on the head coaching radar for a while now. He has interviewed for a whopping 10 vacancies over the past few years while serving as defensive coordinator of the Detroit Lions, according to Dave Birkett of the Detroit Free Press, but he has yet to land a gig.

In 2016, Austin inferred that a few of those interviews were symbolic—meant only to satisfy the NFL's "Rooney Rule" that states a minority candidate must be interviewed for all head coaching vacancies.

Austin told Birkett that wasn't always the case, though.

"Sometimes you can tell when things are good, and some of those interviews, it wasn't cause of the Rooney Rule (that I didn't get the job), it was cause I didn't do very well. But other times you could tell that it was just, 'Hey, we're going to check this box and we're going to move on.' But I think moving forward, that if I have another opportunity, and if things work out that ... I deserve to get one, I'll get one. If not, I'll move on, I'll coach the guys the best way I can and go from there."

Austin withdrew his name from consideration for the Detroit Lions job that went to Matt Patricia after agreeing to become the new defensive coordinator for the Cincinnati Bengals. That Motown miss may have put Austin in prime position to become a head coach soon enough.

It's an understatement to say Marvin Lewis is on shaky ground in Cincinnati. The Bengals like to promote from within whenever possible, and the 53-year-old Austin is one of the more respected defensive coordinators in the league.

If the Bengals struggle again and Lewis gets canned, Austin is set up well to succeed him.

Dan Campbell

To be fair, Dan Campbell has already been an NFL head coach—sort of.

When the Miami Dolphins fired Joe Philbin in 2015, Campbell (then the team's tight ends coach) took over as interim head coach. Campbell's Dolphins went 5-7 over the rest of that season—not terrible by any means, but not enough to land him the permanent job.

Campbell, who cut his teeth as a player under the great Bill Parcells, has an old-school coaching style. The 42-year-old is the tight ends coach for the New Orleans Saints at the moment, although he nearly got a second bite at the head coaching apple this offseason after the Josh McDaniels fiasco unfolded in Indianapolis.

Campbell lost out there to Frank Reich, but he made quite the impression on Colts general manager Chris Ballard, according to Alex Marvez of Sporting News.

"He's been mentored and trained playing under Bill Parcells and coaching under Sean Payton," Ballard told Marvez. "He's got a great vision of what he wants (his team) to be. I think he's going to be an outstanding head coach. It's not a matter of if, but when."

Given Campbell's Parcells pedigree and both playing and head coaching experience, Ballard is likely right. 

Jim Bob Cooter

Jim Bob Cooter has quietly become one of the better offensive coordinators in the NFL over his past few years with the Detroit Lions.

Cooter interviewed for the Detroit vacancy this offseason, but the Lions passed him over in favor of Matt Patricia. 

That Patricia retained Cooter to run his offense speaks to the job he's done.

The Lions were 13th in the league offensively in 2017. That might not seem great, but when you consider that the team had no run game to speak of, it starts to look far better.

Cooter told Dave Birkett of the Detroit Free Press that he expects both the Lions offense and his play-calling to improve considerably in 2018.

"I plan on improving personally every year. I've learned at this point not to think that I have all the answers or even most of the answers. I'm getting better every year. Every year I figure out something that I go, 'Man, a year ago I didn't see it that way and now I do.' I think I understand it better. But this is a complex league. You got to stay fluid."

If that happens, Cooter is going to be a red-hot commodity. Young, offensive-minded head coaches are highly coveted in the NFL after what Sean McVay accomplished with the Los Angeles Rams in 2017.

James Bettcher

When Bruce Arians retired as head coach of the Arizona Cardinals in January, he recommended then-Redbirds defensive coordinator James Bettcher as his successor, according to Dan Duggan of NJ Advance Media.

"I thought he was more than ready to be a head coach and he's one of the best young coordinators in the league. His statistics speak for themselves. But what he did with our defense the second half of our season was amazing, especially when we were out of the playoffs and we just got better and better. Credit to him that our guys kept playing so hard for him."

Bettcher didn't get that job; instead, the Cardinals settled on Steve Wilks as their new head coach. But if he has a successful season as the new defensive coordinator for Giants, he'll soon get his shot.

As we saw with the hires of Mike Vrabel (Tennessee Titans) and Patricia (Lions) in 2018, there's still plenty of demand for bright young defensive minds.

Bettcher fits that bill.

A protege of New York Jets head coach Todd Bowles, the 40-year-old is an aggressive defensive game-planner and excellent motivator. In three years as Arizona's defensive coordinator, the team ranked fifth defensively in 2015, second in 2016 and sixth a year ago. The personnel changed, but the results didn't.

If Bettcher replicates that on one of the NFL's biggest stages in 2018, the head coaching job he covets will likely be his in 2019.

Chris Petersen

Time for some college coaches.

You aren't going to see Nick Saban here. He tried the NFL and didn't like it—or more appropriately, it didn't like him.

You won't see Urban Meyer or Dabo Swinney, either. The chance of either of those coaches leaving wildly lucrative jobs where they have absolute power is approximately minus-34 percent.

However, a jump to the NFL makes more sense for certain college coaches. When NFL.com's Daniel Jeremiah polled five NFL executives to identify head coaching candidates in the collegiate ranks, two singled out Washington's Chris Petersen.

"Petersen would easily be my top candidate," one executive said. "He's an outstanding coach and I know some teams have done their homework on him. Recruiting is such a mess for these coaches. I wouldn't be totally shocked if he decided to make the jump. He would be a home-run hire for any NFL team."

Petersen's something of an elder statesman at 53, and he doesn't have any NFL experience. But in nearly two decades as an offensive coordinator and then head coach at Boise State and Washington, Petersen has proved to be a top-notch offensive strategist and motivator. He transformed Boise State from a tomato can into a national power.

Boise's 2007 Fiesta Bowl upset of Oklahoma is one of the best-coached offensive games you'll ever see.

If an NFL team with a coaching vacancy in 2019 considers the collegiate route, expect Petersen to be on the short list.

David Shaw

Petersen wasn't the only collegiate coach who received multiple votes from Jeremiah's panel. Stanford's David Shaw did as well.

"The short answer—(Shaw) gets it," an exec said. "He doesn't just coach a team; he runs a program. He relates well and he has a solid scheme on both sides of the ball. He also has NFL coaching experience."

That NFL coaching experience the executive alluded to came from 1997-2005, when Shaw was a quality control assistant and position coach for the Philadelphia Eagles, Oakland Raiders and Baltimore Ravens. Since 2007, Shaw has been at Stanford—first as Jim Harbaugh's offensive coordinator and then his successor at head coach.

Shaw's teams at Stanford have won the Pac-12 North five times and the conference itself on three occasions. The Cardinal run a pro-style offense and have produced all sorts of NFL talent, from Andrew Luck to Richard Sherman.

There's one major roadblock with Shaw making the jump to the NFL, however. As Howie Kussoy of the New York Post reported, Shaw insists he's in no hurry to get back to the pros.

"I've coached at that level. I've worked with All-Pro guys and Hall of Fame guys," Shaw said, "and I've coached in every game except for the biggest one, so it's not like, 'OK, that's my goal and I have to get there.' My goal is to do great things at Stanford. If one day that happens, great, but it's not a goal in my career to do that."

For an NFL team to get Shaw to change his mind, it'll take one heck of an offer.

Jim Harbaugh

As frustrating as it may be for Michigan Wolverines fans, you can't write a piece like this without mentioning Jim Harbaugh.

A few months ago, comedian Adam Carolla had Harbaugh on his podcast, and the question of a return to the NFL ranks came up. Harbaugh insisted that he's very happy in Ann Arbor—while simultaneously not saying he had zero interest in going back to the pros.

"My goal, really, is that I'd love to coach 100 players here at Michigan to be NFL players. I'd love to win 100 games here. So this is really personal for me, being at Michigan, for us to have great success in football and our youngsters to have great success in the classroom. I grew up here, I went to college here. I just want to have great success here."

Harbaugh hasn't had "great success" yet—at least not by Michigan's standards. Sure, the Wolverines are better than they were when Harbaugh took the job back in 2015, but they have yet to win a Big Ten championship or beat Ohio State. Harbaugh's Wolverines are 1-5 against the Buckeyes and Spartans, and Michigan's recruiting hauls have been underwhelming as of late.

Neither the coach or the school will admit it, but things haven't gone according to plan for Harbaugh in his return to his alma mater.

This isn't a coach who crawled back to the collegiate ranks with his tail between his legs. Harbaugh was a foot away from winning the Super Bowl with the 49ers.

His return to the NFL may not be especially likely, but it could be tempting if Michigan endures another ho-hum season.

Lincoln Riley

There's been no indication that Lincoln Riley wants to leave the University of Oklahoma. After all, the 34-year-old has only been the Sooners head coach for one year.

But what a year it was.

After leading the Sooners to the College Football Playoff and helping to propel quarterback Baker Mayfield to the Heisman Trophy, NFL teams have taken notice of Riley's offensive acumen.

ESPN college football analyst Kirk Herbstreit said "28, 29, 30" of the NFL's 32 teams reached out to Riley at some point last season to pick his brain about the Sooners' explosive offense, according to Jori Epstein of the Dallas Morning News.

"It wouldn't surprise me at all to see the NFL, within a few years, knock on his door and try to get him to leave," Herbstreit told Epstein. "He's as hot as he can be, as not just a head coach what he did with his first year but also as a playcaller."

Success in college and success in the NFL are two different animals. For every Jimmy Johnson and Pete Carroll, there's a Steve Spurrier, Butch Davis and Chip Kelly. And for as well as the Sooners played on 2017, it's just one season—Riley's first.

But if the Sooners chew up college football again in 2018, some NFL teams will try to talk themselves into Riley being more Carroll and less Kelly.