It's no secret that Ervin Santana pitched below expectations in 2012, which, combined with the fact the Los Angeles Angels have arms to spare in their rotation, led to the team trading him to the Kansas City Royals on Wednesday. However, as mlbinjurynews.com writes, Santana's struggles could've been due to injury.
Santana went from a 3.38 ERA in 228-2/3 innings pitched in 2011 to a 5.16 ERA in 178 innings pitched in 2012. Still only 29 with a career ERA of 4.33, Santana had pitched over 200 innings in three of the four previous seasons. He didn't show any real signs of injury in 2012 and didn't start significantly fewer games, which means the steep decline in innings pitched had to do with him not staying in games as deep as in years prior. The report says that could be a sign of a lingering problem.
Santana also lost over 1 MPH off of his 4-seam fastball and stopped throwing his sinker altogether. He also changed his release point, a common sign of working around an injury.
While it's possible Santana just had a down year and has stayed relatively healthy throughout a decent career, it's also possible some wear and tear is there. It's not known if the Royals just traded for damaged goods, but as the report states, there is evidence there to support the possibility.