Most surprising/disappointing players of the 2018 MLB season

2018 was a dud for catchers, but the Pirates found a potential building block with Diaz. Sharing time with Francisco Cervelli, Diaz is hitting .286-9-30 in 255 plate appearances and playing terrific defense. His .790 OPS is a significant improvement over last season and could spur the Pirates to trade Cervelli in the offseason.

A budding superstar after his first two seasons, Sanchez has struggled at the plate this year when he hasn't been injured. He's hitting just .188-16-47 in 79 games after hitting .278-33-90 last season. With sub-par defense, Sanchez has been a liability for the Yanks, with an OPS below .700.

Aguilar didn't even enter the year as a regular but will finish it as an NL MVP candidate. The powerful first baseman has hit .275-32-99 in 513 plate appearances after serving as a part-time player last season.

There's bad, and then there's what Davis has done this season. The high-price first baseman has hit an embarrassing .174-16-49 with a .553 OPS in 505 plate appearances. He's in only the third year of a seven-year, $161 million contract.

We don't usually expect hitters to have career years at age 34, but that's what has happened this year for Lowrie. A key in the middle of Oakland's batting order, he's hitting .268-21-91 with an .803 OPS in 629 plate appearances. That follows up a 2017 season in which he also posted an OPS above .800 but hit only 14 homers in 645 plate appearances.

An established superstar and arguably a future Hall of Famer, Cano really hurt his case when he was suspended 80 games for PEDs. While on the field, Cano has performed, hitting .279-8-39 in 298 plate appearances, but the suspension certainly hurts the legacy of the eight-time All-Star.

The Yankees began the year with Brandon Drury as their third baseman, but his migraine issues allowed Andujar to step in. He hasn't looked back since then, hitting .298-24-83 in 555 plate appearances, and he is a top candidate for AL Rookie of the Year.

Despite calf issues, Donaldson still managed to hit 33 home runs in 113 games last season. Approaching a walk year, he hoped to rebound to MVP form this year. The calf issues returned to haunt him, resulting in Donaldson playing just 40 games through Sept. 16 and hitting just .227-6-17. His value on the free agent market will be interesting going into his age-33 season.

The Reds had reasonable expectations for Peraza, who replaced Zack Cozart at shortstop. He's done much more than Cincinnati could have hoped for, hitting .293-12-54 with 23 steals in 635 plate appearances. He eventually emerged as the team's primary No. 2 hitter.

After posting a .941 OPS in 109 games last season, there was hope Correa would have an MVP year ahead. That didn't come this season. The shortstop had more injuries and is hitting only .242-14-62 with a .730 OPS through 449 plate appearances, also missing significant time because of the injuries.

Acquired from Atlanta in the offseason in a salary dump, Kemp has been a key contributor for the Dodgers. After a hot start, he's hit .285-19-77 in 479 plate appearances and also significantly improved his defense after showing up in better shape this year.

The Giants didn't expect much from Pence this year, but he's been truly terrible as a part-time player. The veteran is hitting only .209-2-19 with a .540 OPS in 209 plate appearances now in the final year of his five-year, $90 million contract.

The expectations were high for Acuna as one of the top prospects in baseball, but he might have exceeded them. Serving as Atlanta's leadoff man, he's hit .292-25-55 with 14 steals and 71 runs through 98 games. At age 20, he's already looking like a superstar.

Buxton had a terrific second half in 2017, also winning a Gold Glove, so hopes were sky-high for this year. Unfortunately, he's struggled to stay on the field, which is becoming a bit of a trend for his pro career. The Twins didn't promote him in September, likely to limit his service time, after playing only 28 games for the Twins this year.

Injuries and a deteriorated bat had made Markakis one of the worst regulars in baseball before this season. That changed this year, as Markakis, at age 34, leads the NL in hits and doubles while hitting .307/.373/.457 for the first-place Braves.

The Cardinals couldn't figure out how to solve Fowler's hitting troubles before his season likely ended due to a foot injury. He hit just .180-8-31 in 90 games for the Cardinals before the injury.

Much of the hype surrounding Ohtani was for his pitching, but he's been equally impressive at the plate. Hitting in the middle of the Angels batting order, he's hit .290-20-55 with a .956 OPS in only 320 plate appearances. Unfortunately, a torn UCL in his right elbow could prevent him from pitching in 2019.

Ramirez played only 44 games as Boston's regular DH before the Red Sox released him. During that time, he had just a .708 OPS and apparently didn't draw much interest from other teams.

Corbin has had an amazing season in his walk year, going 11-5 with a 3.05 ERA and 230/42 K/BB in 186 innings. That came after posting a 4.03 ERA last year. The lefty is set to become extremely rich this offseason.

Stroman missed much of spring training with a shoulder injury, and his season has gone downhill from there. The extreme groundball pitcher is likely finished for the year, posting a 5.54 ERA in 19 starts after throwing 200-plus innings in consecutive seasons.

A starter for the vast majority of his MLB career, McHugh was forced to the pen because of Houston's depth. He's been arguably the Astros' best reliever this season, posting a 2.15 ERA and 88/19 K/BB in 67 innings. McHugh also has vultured five wins.

Shaw was a true workhorse and setup man for Cleveland since 2013, earning him a three-year, $27 million contract with the Rockies. But the move to Colorado hasn't been kind to Shaw, with his 6.27 ERA in 58 appearances.

St. Louis paid veteran closer Greg Holland big money on Opening Day to be its closer, but he never panned out. Instead, Norris has been in the role for most of the year, just as he was with the Angels last season. Although Norris has struggled late in the year, he has a 3.49 ERA in 56.2 innings and has converted 28 saves.

Knebel emerged as Milwaukee's closer and was an All-Star in 2017, but everything has changed this year. He suffered a hamstring injury early in the year and has had trouble keeping the ball in the park since then. He had an ERA above 4.00, and Milwaukee has been forced to turn to other relievers to close for much of the season.

Not much was expected for the A's this season, but they're well on their way to a wild card berth. Oakland has managed to find success despite several major injuries to its starting staff, instead finding effective innings from the likes of Brett Anderson and Edwin Jackson.

The Nats fired Dusty Baker after continuously falling short in the playoffs. They turned to Martinez this year, a former bench coach under Joe Maddon who has regularly had managerial interviews. The Nats are now well out of the playoff race and just hoping to finish above .500.