After his last performance, a strong seven inning, one run effort against the Orioles, Bruce Chen has been placed on the disabled list due to a lat strain on his left side. The injury doesn't appear to be anything serious, but with plenty of depth in their rotation at AAA, the Royals made what I feel is the right decision to protect Chen.
That Chen is still in the rotation to protect at all however is something I find a little bit surprising. When he resigned I wrote that, "Chen is essentially the definition of a back-end junk-baller. With a fastball that averaged just 86.2 last year, he's not going to throw the ball by anyone, but he's got five pitches and he'll throw them all at you. That helps him keep hitters off balance, but doesn't keep him from being eminently hittable."
So of course as we head into mid-May Chen is working on a 3.59 ERA in 42.2 innings of work. Naturally. He's still working with the same smoke-and-mirrors stuff that led him to a 4.17 ERA in 2010, but his FIP marks continue to suggest that his success is nothing more than that. In fact, despite the decreased ERA, Chen's peripherals have actually gotten worse - not better after what was an underwhelming showing in 2010. His K rate has dropped by 1.23 points and he's done nothing to change his status as one of the most fly-ball prone pitchers in the league, inducing ground balls at just a 33.8% clip.
Despite the negativity that an observer such as myself has about the raw stuff and the combination of parts that leads to his whole, Chen has been remarkably consistent now over the past 183 innings with the Royals. How long that'll continue? Hard to say. But for a team that had a chance to run out a rotation that could've collapsed on itself, Chen has been a remarkably consistent and steady force.
In his place the team will rely on Vin Mazzaro who was one of the players acquired from the Athletics in this winters David DeJesus trade. Like Chen, Mazzaro is a thoroughly underwhelming pitcher when observed by his peripherals only, but also like Chen, he was surprisingly effective in 2010, posting a 4.27 ERA in 122 innings despite a 5.13 FIP.
I expect that he'll be expected to make at least two starts before Chen is ready to return. It'll be a big chance for Mazzaro to show the big league team that he has the stuff to succeed at the next level because he's going to start getting edged out quickly by the gathering wave of prospects preparing to inundate the Royals rotation.