Jason Kipnis was an MVP candidate during the first half of the season. His 4.1 fWAR were second to only Mike Trout during that time. He came out of the All-Star break playing just as well, and at the end of play on July 29, his batting line was a robust .333/.408/.489, with a wRC+ of 148.
Kipnis' shoulder began bothering him though, and after a bad series against Oakland, he was placed on the DL. He missed the Indians' next 14 games, returning to the lineup on August 18. In the month since his return, Kipnis has hit just .190/.243/.320 in 107 plate appearances, with a RC+ of just 50.
Those differences are dramatic.
If there were no interruption in his season, no known injury, one might reasonably argue that he was just having an extended slump. Those 107 plate appearances are a decent chunk of playing time though, and more significantly, we do there was an injury, which I think raises the question, Is there an injury?
Early in 2014, Kipnis landed on the DL with a strained oblique. He missed a month, and never looked right after returning, batting just .241/.299/.315 the rest of the season. The speculation has been that he wasn't fully recovered from the injury. Whether that's true or not, we can't really know. I can't be the only one whose started to have flashbacks to his struggles though, and can't be the only one wondering if he's again come back too quickly from an injury that needed more time to fully heal.
Aside from the semi-small sample we're dealing with, one looking to argue against a lingering injury can point to Kipnis' .233 BABIP during the last month. Even if you give him his career BABIP (.317) though, he'd still only be batting .250, with a slugging percentage somewhere near .400. Kipnis' walk rate through July 29 was 10.4%, but since his return it's dropped to 6.5%. His strikeout rate through July 29 was 14.3%, but since his return it's spiked to 23.4%.
Whether it's because his shoulder is still bothering him, or it's something else, Kipnis has not been the same player he was since the shoulder first became a problem in late July. His desire to get back on the field is understandable, but it seems possible he's talked his way back before he was ready. If that's not the case, we're free to take comfort in him being healthy, but in some ways that would be worse, because it would provide no explanation for why he's struggled during the last month.