The Pirates have re-signed pitcher Jeff Karstens to a one-year deal believed to be valued in the region of $2.5M, pending a physical. While Karstens will enter the mix for the final two spots in the rotation, he is most likely to be guaranteed a spot if no other starting pitcher is acquired prior to the beginning of the season.
Karstens should help solidify a rotation that has question marks after Wandy Rodriguez and A.J. Burnett. He was non-tendered earlier this winter due to durability concerns, with the club moving onto sign former Twins lefty Francisco Liriano. However, Liriano picked up a so-far-undisclosed injury that had forced renegotiations to the two-year, $12.75M deal that was agreed shortly before Christmas, although Karstens’ deal now places doubt on any agreement with Liriano.
Despite a strong showing in limited time last season, Karstens has received very little interest since he was non-tendered by the Pirates - with only the Colorado Rockies rumored to be tracking the righty. In 90.2 innings last season, Karstens had a 3.92 ERA. His FIP was more than half a run lower at 3.32, although his xFIP (3.84) and SIERA (3.89) sided more with his conventional earned run average.
Karstens’ value last season was varied over versions of WAR. FanGraphs’ version, which is based on FIP, valued him as 1.7 wins above replacement pitchers, a career high for the righty despite the low number of innings. Both Baseball Reference (0.6 WAR) and Baseball Prospectus (0.8 WARP) valued Karstens lower, although Baseball Prospectus also saw Karstens’ 2012 as the best year of his career. If he’s healthy, Karstens should be worth at least 2.0 WAR and probably more. If not, then the club can then rely on whichever pitcher(s) now ends up as minor league depth after Spring Training - although Karstens should provide an upgrade to the rotation whenever he is available to make his starts.
With the Francisco Liriano discussions possible continuing and rumored interest in Shaun Marcum; the club would have the payroll space to make a further addition. Nonetheless, Jeff Karstens should become a dependable arm at the back end of a rotation whether another starting pitcher is acquired or not. His ability was never in question, Neal Huntington admitted that if he’s healthy and pitches like he did over 2011-12 then non-tendering the pitcher would have ended up being a mistake. However, the reunion now sees the club avoiding such a mistake while signing Karstens to a deal less than the projected $3.8M he would have received through arbitration.