The winter meetings are here, which means the free-agent and trade rumors will hit full throttle as teams look to fill their missing holes. In some cases, however, the best chance for a team's improvement comes not from making a big trade or signing, but by having a veteran return to form. Here are five such high-priced guys and how they affect their team's winter meetings plans:

Ryan Zimmerman, Washington Nationals (3 years, $48 million): The rumors around the Nationals have them going after Andrew McCutchen and Chris Sale, but neither of those players addresses the Nationals' biggest problem in 2016: first base. Zimmerman hit .218/.272/.370 in 115 games, and the Nationals ranked last in the majors in wOBA at first base. Acquiring McCutchen would presumably move Trea Turner to shortstop, his position in college and the minors, making Danny Espinosa trade bait or a utility guy. Going after McCutchen and hoping for a bounce-back season is a reasonable risk, although you potentially downgrade defensively at both center field and shortstop. You could try Jayson Werth at first base and keep Turner in center field, with McCutchen in left, or maybe try Turner at second and slide Daniel Murphy over to first. But it seems Zimmerman is still the starter for now.

Aside from that, there is reason to believe Zimmerman will be more productive in 2017. Tony Blengino, who contributes to ESPN Insider, writes a hitter contact-quality report at FanGraphs, looking at the exit speed and launch angle of each ball put into play. Tony writes on Zimmerman:

His overall, liner and grounder authority paced NL first basemen, and his fly-ball authority was well above average as well. Expect serious upward regression in his liner rate moving forward, with a possible upward move in his fly-ball rate as well. His walk rate did take a major hit last season; positive regression is possible here as well, as his walk-rate percentile rank was higher than his K rate percentile rank each qualifying season from 2009 to 2015. This guy is not through just yet.

So Zimmerman's batted-ball profile was that of a hitter who should have put up better numbers. Of course, Zimmerman's health is an ongoing issue, and the 115 games were his most since 2013. ZiPS forecasts a .238/.295/.401. That's still not good enough for a first baseman, so it would at least be wise for the Nationals to have a backup plan.

Pablo Sandoval, Boston Red Sox (3 years, $59.8 million): After a disastrous debut season with the Red Sox in 2015, in which bad hitting and bad defense led to a minus-0.9 WAR season, Sandoval played just three games in 2016 after going down with a left shoulder injury. Now the Red Sox have to determine how he fits into their plans. Red Sox third basemen, mostly Travis Shaw with some Aaron Hill and others, ranked last in the majors in wOBA with a .242/.306/.380 batting line.

Yoan Moncada is likely the eventual answer at third base, but he has played just 53 games above Class A and only a handful at third. He could use a little more seasoning in the minors, giving Sandoval half a season to prove himself, with Shaw and Brock Holt around as secondary options. If Moncada is deemed ready, the Red Sox could consider Sandoval for the DH role rather than spending more big money to bring in Edwin Encarnacion (or a lesser amount for another DH).

Jordan Zimmermann, Detroit Tigers (4 years, $92 million): I thought this was a big red-flag signing last year. Zimmermann was moving from the weak-hitting National League East to the American League while coming off a season in which his strikeout rate had dropped and his home run rate had increased. He had a 0.55 ERA through April, although he wasn't striking many guys out. The rest of his season was all downhill, including groin and neck injuries that limited him to 18 starts. He finished with a 4.87 ERA and 14.7 percent K rate that was 5 percent below his career average.

Reports say the Tigers are trying to retool by trading some high-salary vets while remaining competitive at the same time. Miguel Cabrera even told Venezuelan reporters during the weekend that while he'd like to remain in Detroit, he would not stand in the way of a trade. Zimmermann won't be traded -- no team will want his contract after a bad season -- but a Zimmermann bounce-back could give the Tigers a solid rotation with Justin Verlander, Michael Fulmer and the upside of Daniel Norris and Matt Boyd, perhaps freeing them up to trade a J.D. Martinez or Ian Kinsler for some younger talent.

Zack Greinke, Arizona Diamondbacks (5 years, $172.5 million): Greinke wasn't near as bad as the three guys above, and while he did go 13-7, his 4.37 ERA was disappointing, and some minor injuries limited him to 26 starts. At $34 million and then up to $35 million in the next four years, a trade is unlikely. As Mark Simon wrote the other day, however, one thing that could help Greinke and the other Arizona pitchers: Veteran Jeff Mathis, a good pitch-framer, was brought in to replace Welington Castillo, who wasn't offered a contract.

With Greinke, Robbie Ray (fifth-best strikeout rate among starters), the just-acquired Taijuan Walker, Shelby Miller, Braden Shipley and Archie Bradley, there's a lot of potential for this rotation to improve on its second-worst ERA in the majors. You can't expect Greinke to repeat his sub-2.00 ERA of 2015 with the Dodgers, especially playing in Arizona, but 200 innings and an ERA in the high 2s would help redeem his $206 million contract.

Felix Hernandez, Seattle Mariners (3 years, $81.6 million): Like Greinke, Hernandez wasn't terrible in 2016, but his ERA has climbed from 2.14 in 2014 to 3.82, and his WAR has decreased from 6.8 to 1.6. He doesn't throw hard anymore, which led to more walks as he wasn't challenging hitters as much -- or, with the difference between his fastball and changeup velocity only a couple of miles per hour, hitters simply learned to lay off that hard changeup as it dipped outside the strike zone.

The Mariners have loaded up on offense, but trading Walker thins out the rotation depth. Keep in mind that when Hernandez signed his extension in 2013, the two sides agreed to a $1 million team option for 2020 if Hernandez spent 130 consecutive days on the DL with a right elbow injury. This is a similar clause John Lackey had with the Red Sox, basically a protection against Tommy John surgery. There was some concern about the elbow in 2013; it's now four years later and Hernandez has pitched 795 innings since signing that deal. Jerry Dipoto will look to add another veteran starter -- Doug Fister is one rumor -- but Dipoto's plan to add offensive depth only works if Felix stays healthy and morphs into a Kyle Hendricks type who can still dominate with below-average velocity.