The San Francisco Giants have acquired a three-time All-Star and Gold Glover to play third base, thereby adding a significant upgrade over what remains of Pablo Sandoval.

Now all they need is more.

A lot more.

For now, Evan Longoria is the newest Giant. They acquired him on Wednesday from the Tampa Bay Rays in a blockbuster deal, the details of which Marc Topkin of the Tampa Bay Times has the full readout:

"We are pleased to bring Evan Longoria to the Giants organization," said Giants general manager Bobby Evans, via SFGate.com. "Evan gives us a Gold Glove-caliber player at third base and also provides us a middle-of-the-order presence in the lineup. His durability and leadership will strengthen our club moving forward."

Longoria, 32, will serve as the Giants' everyday third baseman in 2018 and beyond. He's one year into a six-year, $100 million contract that runs through 2022 with an option for 2023.

Nobody should need to be sold on his being an upgrade over Sandoval, but some numbers are in order anyway. Over the last three seasons, Sandoval has averaged 69 games, a .644 OPS and minus-0.8 wins above replacement (via Baseball Reference). Longoria's averages in this span: 159 games, a .781 OPS and 3.5 WAR.

But if the Giants are hoping that he'll be a one-man fix for a team that lost 98 games in 2017, well, they're sorely mistaken.

Longoria's calling cards are power and defense. The latter remained strong enough in 2017 to add Gold Glove No. 3 to his collection. The former fell flat, however, as his home run total dropped from 36 in 2016 all the way down to 20.

The big red flag is how Longoria went from being a leading member of Major League Baseball's air-ball revolution to being largely absent from it. He achieved a career-low ground-ball rate (32%) in 2016, only to turn around and post a career-high rate (43%) in 2017.

And now comes the obligatory reminder that AT&T Park is no country for sluggers. When all the home runs Longoria has ever hit are measured against its dimensions, a handful fall short of the fence:

It's not at all unbelievable that the acquisition of Longoria barely moved the needle for the 2018 Giants' record projection at FanGraphs. They were projected to win 80 games. Now they're projected to win...[drum roll]...81 games.

Whether this is a true reflection of their quality is negotiable. But it speaks not just to Longoria's less-than-almighty ability, but also to how many holes the Giants must still fill.

They needed a center field upgrade even before they salary-dumped Denard Span on the Rays. With Gorkys Hernandez now projected as their everyday center fielder, that need looms even larger.

The other outfield spots also lack solid foundations. In right field, the Giants have an aging Hunter Pence who hasn't had a healthy, productive season since 2014. In left field, they're set to go with a Jarrett Parker/Mac Williamson platoon that failed to make an impact in 2017.

With Matt Moore having been traded to the Texas Rangers, San Francisco's starting rotation is Madison Bumgarner, Johnny Cueto, Jeff Samardzija and then two spots that are more or less open.

On the bright side, the Giants have Buster Posey, the best catcher in baseball, behind the plate and one of the best infields in MLB with Longoria at third, Brandon Crawford at shortstop, Joe Panik at second base and Brandon Belt at first base.

But in an NL West division with three 2017 postseason teams—most notably the reigning National League champion Los Angeles Dodgers—it's hard to argue that the Giants are destined to go places as long as they need solutions for 100 percent of their outfield and 40 percent of their starting rotation.

According to Bob Nightengale of USA Today, the next shoe to drop may be the signing of free-agent slugger Jay Bruce:

He would fix one of the corner outfield spots, but not center field.

So while they're looking at Bruce, the Giants should also consider signing Lorenzo Cain. If they prefer someone younger, they could rekindle their trade interest in Cincinnati Reds speedster Billy Hamilton, for whom Ken Rosenthal of The Athletic reported they were the "strongest" suitor.

On the pitching front, Yu Darvish and Jake Arrieta are the top prizes on the free-agent market. Lesser prizes include Lance Lynn, Alex Cobb and Andrew Cashner.

On the trade market, the Giants might turn back to the Rays and ask about Chris Archer. Of course, since he's ultra-talented and signed for cheap through 2021, that would mean sacrificing some combination of outfielder Heliot Ramos, slugger Chris Shaw and right-hander Tyler Beede from their farm system.

Regardless of how the Giants choose to continue their renovation, seeing it through to a rational end will be severely costly. Indeed, there's a good argument that they simply can't afford that.

Without Arroyo, a farm system that Bleacher Report ranked at No. 26 at the end of the minor league season is now even worse. And while the final picture won't be clear until the amount of cash going from Tampa Bay to San Francisco is known, it's a safe assumption that the Giants have even less than the $15.5 million in luxury-tax space that they started with on Wednesday.

And that's just for 2018. As noted by Jeff Passan of Yahoo Sports, the long-term outlook of San Francisco's payroll is even worse:

With this ahead of them and their last World Series championship now three years behind them, the Giants could have been forgiven if they were committed to rebuilding this winter. But they made it clear with their hot pursuit of Giancarlo Stanton that they're not ready to do that. With the Longoria trade, they officially committed to not doing it.

The only explanation is that the Giants view their long-term future as far more hopeless than their short-term future. Rather than punt on all of it, better to try and make the most what short-term hope they have.

So be it. But to make the most of it, they need more.

Stats courtesy of Baseball Reference, FanGraphs and Baseball Savant. Payroll and contract data courtesy of Cot's Baseball Contracts.