A larger sample is always preferable for evaluating players, but not everyone gets that opportunity.
Some are limited, whether due to injuries or time in the Minors, but make the most of their time in the big leagues. That was the case for the players below, each of whom logged less than a half-season's worth of MLB playing time in 2018 but authored performances that should create optimism for '19.
Setting aside rookies getting their first taste of the Majors, here is a look at five of the most intriguing partial seasons from last year that you might have overlooked:
Ji-Man Choi, DH/1B, Rays
A native of South Korea, the 27-year-old Choi signed with the Mariners way back in 2009 but entered '18 with only 147 big league plate appearances to his credit. He began the season by scoring the winning run for the Brewers on Opening Day, but Choi bounced between Milwaukee and Triple-A Colorado Springs until he was traded to Tampa Bay on June 10 and sent to Triple-A Durham.
The Rays recalled Choi a month later and gave him that long-awaited opportunity. The left-handed slugger took advantage, slashing .269/.370/.506 with eight home runs in 49 games. Choi's park-adjusted 141 Weighted Runs Created Plus with the Rays tied for 27th in MLB from July 11 on (min. 150 plate appearances), and he posted a 153 mark against right-handed pitchers. With discipline and pop, Choi could have a regular role in the Tampa Bay lineup again in 2019, at least as part of a platoon.

Tony Cingrani, LHP, Dodgers
It was mostly a frustrating season for the lefty reliever, who spent the majority of it on the disabled list with shoulder problems and otherwise posted a 4.76 ERA across 30 appearances before getting left off the Dodgers' postseason rosters. That might make Cingrani a forgotten man in the L.A. bullpen, but assuming good health, there is reason to believe the 29-year-old could be a force in relief this year.
Among all pitchers with 20-plus innings in 2018, Cingrani ranked ninth in strikeout rate (37.9 percent) and sixth in the difference between his strikeout and walk rates (31.6 percent), behind only Edwin Díaz, Josh Hader, Sean Doolittle, Chris Sale and Dellin Betances. Each of those feared arms had an ERA of 2.70 or lower, and Cingrani's 2.32 Fielding Independent Pitching is more representative of how well he pitched. Cingrani put up similarly robust peripheral numbers in 22 games for the Dodgers after being acquired from the Reds at the 2017 non-waiver Trade Deadline, so a full season in L.A. could work wonders.

Trevor May, RHP, Twins
It's been a long road for May, who may finally be primed for a breakout. The 6-foot-5 righty, once a highly regarded prospect, struggled as a starter early in his Twins career, showed promise but inconsistency after a shift to the bullpen, then underwent Tommy John surgery before the 2017 season. May returned to the Majors at the end of July last year and, at 29, now seems ticketed for a high-leverage role in 2019 -- perhaps even as Minnesota's closer.
May got back to the Twins with his pre-surgery velocity intact and looked sharp. In a small sample (24 games, 25 1/3 innings), May generated a higher whiff rate on his four-seam fastball (35.2 percent) than any pitcher other than Hader, while holding opponents to 3-for-32 (.094) with 14 strikeouts on his curveball and changeup. That nasty stuff gave May a gap between his strikeout rate (35.0 percent) and walk rate (4.9 percent) that ranked right behind Cingrani.

Adalberto Mondesi, SS, Royals
Entering 2018, Mondesi's top-prospect status had lost some of its luster, as he carried a career line of .181/.226/.271 in the Majors, having failed to establish himself in Kansas City. Mondesi then began the season on the DL and upon getting healthy, returned to Triple-A.
He was recalled in mind-June and started slow, but everything soon clicked. Mondesi, who turned 23 in late July, batted .294/.326/.541 over his final 58 games, combining 13 home runs with 28 steals. His 32 total swipes (in 37 tries) ranked eighth in the Majors despite his 75 games played, with Mondesi just the sixth modern player to finish with that many steals in less than half a season. According to FanGraphs Wins Above Replacement, the speedy switch-hitter was one of MLB's 15 most productive position players after the All-Star break.

Tyler White, 1B/DH, Astros
After Alex Bregman, which Houston hitter put up the highest OPS last year? It wasn't José Altuve or George Springer. It was White (.888), whose 66 games came mostly in the second half after a stretch spent tearing up the Pacific Coast League.
Once a 33rd-round Draft pick, White is already 28, but his .287/.350/.551 line in roughly 200 plate appearances after the All-Star break gave him a 147 wRC+ that placed him right between Paul Goldschmidt and Khris Davis. With Evan Gattis and Marwin Gonzalez free agents, Houston has more room at first base and DH this year, so the door seems open for White to grab a big role if he can carry over his 2018 success.