At this time of year, many teams are searching for upgrades, whether by throwing money at free agents or addressing needs via the trade market.
Both are worthy pursuits, but improvement can come from within, too.
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With that in mind, here are nine players whose teams need them to step up in 2019. None had the sort of success that was expected this past season, with injuries a common thread, but each will need to play a bigger role as they chase the postseason.
Kristopher Bryant, 3B/OF, Cubs
His first three seasons were about as good as it gets, as Bryant won Rookie of the Year and MVP Awards, plus a World Series championship, while ranking third in the Majors in FanGraphs' wins above replacement (WAR). But a left shoulder injury sent him to the disabled list twice in 2018, limiting him to 102 games and a modest 2.3 WAR. His power sapped, Bryant slugged just .387 from mid-May on, and his numbers fell pretty much across the board. As he heads into his age-27 season, a Cubs club trying to climb back to its perch atop the division would love to see the 2015-17 version of Bryant return. General manager Jed Hoyer said recently that Bryant "looks great," and Steamer still projects him to lead the National League in WAR.

Carlos Correa, SS, Astros
This is a similar story to Bryant's. Correa arrived in the Majors in 2015, was Rookie of the Year, and over his first three seasons established himself as one of the best shortstops in baseball as his team won a World Series. Then, in '18, another promising season was derailed by physical issues. In Correa's case, a sore back took him out of action for about six weeks, and he posted a mere .517 OPS in 37 games after returning, dragging down his overall numbers (.239/.323/.405). Still just 24, Correa should benefit from an offseason of rest -- and being able to breathe unrestricted -- as Houston tries to reclaim its title.

Corey Seager, SS, Dodgers
Seager has followed a similar path to Bryant and Correa, but the 2016 NL Rookie of the Year is trying to return from even more serious physical issues. After playing in just 26 games this past season, Seager underwent Tommy John surgery on his throwing elbow, and then in August, had surgery on his left hip. The Dodgers acquired Manny Machado to play shortstop last summer, but all indications are that was a short-term fix only, and Seager is back to running, throwing and swinging a bat after months of rehab. While L.A. has the depth to survive more missed time, getting Seager back in form -- he ranks right behind Bryant in the Steamer WAR projections -- would be a huge boost in the quest for a seventh straight division title.
William Fowler, OF, Cardinals
The Cardinals splurged on a five-year, $82.5 million contract to pull Fowler away from the Cubs after 2016, and while the switch-hitter's first season in St. Louis wasn't a complete success, he was well above average at the plate (.264/.363/.488, 121 wRC+). Then, the bottom fell out. Moved from center to right in his age-32 season, Fowler started slow and never got going, as his OPS peaked at .654 and was at .576 when he sustained a season-ending left foot fracture in early August. The struggles took a mental toll, but 2019 could offer a clean slate. Assuming St. Louis doesn't swoop in to acquire Bryce Harper or another notable outfielder, Fowler will get a chance to rebound and help end a three-year postseason drought.

Gary Sanchez, C, Yankees
"He's part of our solution," general manager Brian Cashman recently said of Sanchez, whose 2018 featured a .186 batting average, lots of strikeouts and passed balls, and two stints on the DL due to a groin injury. It was quite a setback for a guy who over the previous two years was easily the best offensive catcher in baseball. In 175 games over that time, Sanchez batted .284/.354/.568 with 53 homers. Between his thunderous bat, rocket arm, poor luck last year, and the fact that he was playing through a shoulder issue that required offseason surgery, there are plenty of reasons to think Sanchez will be a force again in '19.
Byron Buxton, CF, Twins
As disappointing as 2018 was for the Twins as a team, it was even more so for Buxton individually. He played in only 28 Major League games, batting .156/.183/.200 and spending time on the DL with migraines and a toe fracture. Buxton returned from the latter injury in June and hit well at Triple-A Rochester, but wasn't recalled when rosters expanded on Sept. 1, sparking some understandable frustration. With that said, 2019 brings a new manager (Rocco Baldelli) and a fresh start. Buxton showed in '17 that his elite center field defense and baserunning make him highly valuable, even when his bat is below average. The former top prospect only just turned 25, and could play a key role in a Minnesota revival.

Adam Eaton, RF, Nationals
This isn't a performance issue. Washington got the player it wanted when it acquired Eaton in a big trade with the White Sox two years ago, with Eaton batting .300/.394/.422 (123 wRC+) since then. Unfortunately for both sides, knee and ankle injuries have held him to a total of 118 games during that time. Assuming Harper doesn't return, the Nats need to finally have a healthy Eaton playing alongside young phenoms Juan Soto and Victor Robles, and getting on base at the top of the lineup. Given how competitive the NL East looks, that could make a big difference.
Kevin Kiermaier, CF, Rays
Coming off a 90-win season that still left them out of the postseason picture, the Rays are working hard to upgrade their roster. A full season of peak Kiermaier would go a long ways. While he remained a stellar defensive center fielder and baserunner in 2018, Kiermaier's batting line sunk from above average to .217/.282/.370. A torn thumb ligament that sidelined him from mid-April to mid-June likely played a role, and Kiermaier also sustained a hairline fracture in his right foot in late September. The 28-year-old could be part of an intriguing outfield next year, along with '18 trade acquisitions Tommy Pham and Austin Meadows.

Zack Cozart, 3B/2B, Angels
The Angels need to get the most out of what they have as they try to fight their way into the postseason for only the second time in the Trout Era. That wasn't the case last season with Cozart, who signed a three-year, $38 million deal after a breakout, 5-WAR season for the Reds. While Cozart helped out playing second, third and shortstop, he lost nearly 300 points of OPS while batting .219/.296/.362 before undergoing surgery on a torn labrum in his left shoulder. With little margin for error in a division with the Astros and A's, the Angels could use something closer to the 2017 Cozart.