The Indians announced that Michael Bourn underwent what is being termed a "minor" surgery on his left hamstring Tuesday, to repair damage suffered on the final day of the regular season during a stolen base attempt (Bourn was able to play in the Wild Card Game three days later, but went 0 for 4). The procedure is called a "distal hamstring debridement,' and involves operating at the point where the tendon attaches behind the left knee. Doctors say Bourn will be able to begin rehabbing later this week, and that he'll be back to regular offseason activities (bowling? fishing? building a barn?) in 4 to 6 weeks.
This doesn't seem like cause for serious concern, but it does re-raise questions about Bourn's durability going forward, and about how well his speed might hold up. Bourn averaged 52 stolen bases from 2010 to 2012, with an 80% success rate. In 2013, he stole only 23 bases, at only a 66% success rate. His defense also went from outstanding in 2012 to only mildly above average in 2013.
Bourn is signed for 3 more years at a total cost of $41 million (he also has a $12 million option for 2017 which vests if he has 550 PA in 2016). So much of his value is tied up with his speed. Leg muscle injuries are obviously not good for a player's speed, and while the operation may get him right back where he was (and as I said, it has been called "minor"), I find it hard not to view this as a red flag.