At the outset of the 2013 season, a realistic hope would be that Wei-Yin Chen could survive the whole season in the starting rotation as a league average pitcher. This is exactly what he did in 2012, being the only Orioles pitcher to start more than 20 games that season. Between either injuries or ineffectiveness, no one else made it through the whole season as a starter. Given the uncertainty at the back end of the rotation, Chen figured to be an important part of whatever the Orioles hoped to accomplish.
Unfortunately for both Chen and the Orioles, a strained oblique he suffered in the middle of May knocked him out of commission for about six weeks. In the time that Chen spent on the disabled list, the Orioles had games started by the likes of Freddy Garcia, Kevin Gausman, T.J. McFarland, and Jair Jurrjens. Chen's injury led to Gausman being brought up to the majors, probably before he was ready to come up, given his results. The nine starts that Chen missed were replaced by a lot of suck.
Chen made 23 starts in 2013, throwing 137 innings in those games, an average of just shy of six innings per game started. He had a 4.07 ERA, which is good for a 103 ERA+, meaning that, when taking park factors into consideration, he was slightly better than league average.
While he was still prone to giving up home runs, he cut his HR/9 rate from 1.4 in 2012 to 1.1 this season. His walk rate per nine innings was a respectable 2.6. Most teams in baseball, including all of the Orioles division rivals, would have liked to have Chen's results over what they actually got from their 4th and 5th starters.
Chen is not Cy Young, but he is a pitcher who has value to the Orioles, especially for a team-friendly salary of $3.75 million. He will make about $4.1 million in 2014, with a $4.75 million team option for 2015 and the Orioles having two arbitration years beyond that, if they so choose.
In terms of his ERA, Chen's first two MLB seasons don't look much different, but how he got there is interesting. His rookie season was marked by struggles in the first inning, to the tune of a 5.91 ERA opening up games. The 2013 season saw him much better in the first inning, with a 2.35 ERA. That means he struggled later, and it shows in how batters performed against him the third time through the order: a .774 OPS allowed the third time through in 2012 became a .925 OPS allowed the third time through in 2013.
It looks to add up to Chen having a six-inning arsenal, though he struggled in the fourth inning both years as well. Perhaps middle-of-the-order bats adjust better to Chen the second time around than Chen adjusts to those batters.
Chen is also a pitcher with bad luck to have to face teams like the Yankees and Red Sox often. He faced the Red Sox most often, making four starts and giving up 17 runs in 21 innings. That is a 7.29 ERA. Against the Yankees, he made three starts, giving up 11 runs in 16.1 innings, a 6.06 ERA.
This is not to say that Chen is only good against bad teams, because he had a better ERA against winning teams (3.97) than losing ones (4.32) while making nearly two-thirds of his starts against winning teams. This was the case last year as well. For comparison, a Cy Young contender like Max Scherzer made just over half his starts against winning teams, and another, Yu Darvish, started more than half of his games against losing teams.
If the Orioles coaches are able to help Chen with some of his third time through the order struggles, he could take a step forward as a pitcher. Perhaps he needs to work on mixing up his arsenal as he tires later in a game. Perhaps he is just a six-inning pitcher, which manager Buck Showalter would do well to heed. Chen had a 10.57 ERA in the seventh inning in 2013.
A pitcher who can dependably go six innings is still a valuable starter. In an ideal world, Chen would not be higher than the third-best O's starter, if not lower. He will be an important part of the rotation to whatever end the O's aspire to reach.
Nothing about his overall numbers are exceptional, but the Orioles and their fans would have much rather seen Chen than the pitchers who made starts instead of him. If he makes every start again in 2014, the team should be in that much better shape because of it.