A partially-torn elbow ligament was to blame for Wei-Yin Chen’s extended stay on the DL in 2016. The Miami Marlins hope the lefty can remain healthy and rebound this year.

The Miami Marlins signed Wei-Yin Chen prior to the 2016 season to be a quietly steadying force in their rotation, much like he was for the Baltimore Orioles over the previous four years. To this point, the left-hander has not justified the five-year, $80 million investment the Marlins made in him.

However, we now have some clarification on just what has been ailing Chen since his move to Miami. According to Tim Healy of the Sun Sentinel, the 26-year-old and the Marlins discovered a partial tear in the ulnar collateral ligament (UCL) of his left elbow last summer when he was on the disabled list with a reported elbow sprain.

Chen did not have Tommy John surgery to correct the tear, instead receiving a platelet-rich plasma (PRP) injection and treating the injury with rest and rehab. It’s the same strategy undertaken by Yankees pitcher Masahiro Tanaka, who was also diagnosed with a partial UCL tear.

The Taiwanese hurler acknowledges that without surgery, the torn ligament is something he will need to closely monitor as he pitches. Per the Sun Sentinel:

“With the tear in the ligament, it doesn’t really heal,” Chen said through translator Louis Chao. “It’s still there. It won’t heal. So I don’t really think about if it’ll get worse or not. I just think about with this, what treatment I should be getting.”

Healey mentions that Chen is paying particularly close attention to his mechanics; if they get “out of whack,” he could aggravate the tear.

The need to handle Chen more carefully was on display during his start last Tuesday night against the Mariners. The southpaw held Seattle hitless over seven innings while issuing two walks and striking out two. However, with Chen’s pitch count at 100, manager Don Mattingly decided to remove him from the game rather than continue pursuing the no-hit bid. It’s safe to say Mattingly made the wise call, especially this early in the season.

For Chen, the 2017 campaign so far has been a case of “two out of three ain’t bad.” Aside from Tuesday’s strong outing, he also turned in a solid performance in his season debut against the Mets. He tossed six innings (86 pitches), allowing one run on seven hits and a walk with five strikeouts.

Chen’s second start of the year was far less memorable, however. He lasted just three innings against those same Mets, surrendering six runs on seven hits, including two home runs. Overall, it’s the same kind of unevenness we saw from Chen in 2016. He posted a career-high 4.96 ERA over 123.1 innings along with a 1.28 WHIP and 4.17 K/BB ratio.

The Marlins want to see the pitcher who produced a 3.34 ERA, 1.22 WHIP and 3.73 K/BB for the O’s just a year earlier while logging 191.1 frames. That might be on the optimistic side, but Chen has already proved he can still register quality outings.

Chen can opt out of his deal after this season, and the Marlins probably won’t mind if he puts together a solid year and decides to test the market again. If he stays in, he will earn $59.8 million over the following three seasons. (Not to mention a $16 million vesting option for 2021.) That’s a lot to pay a pitcher over 30 with health-related question marks.

For now, Miami will hope Chen can stay on the field and help this year’s team. He’ll get some extra rest and take the mound again next Tuesday against Vince Velasquez and the Phillies in Philadelphia.