Orthopedic surgeon Lewis Yocum will perform the surgery, which will involve repairing the SLAP tear in Klein's labrum that a previous MRI revealed, as well as whatever else needs to done to fix the area. The rehab and recovery will depend on the scope of what's done, which won't be known until Yocum can get in there and see what's going on.
Klein was already doubtful to throw a pitch the rest of the season after an MRI taken in June revealed the SLAP tear, and attempts to rehab the injury ended when he experienced pain while throwing last week.
The 23-year-old went 3-1 with a 1.11 ERA between Double-A Bowie and Class A Frederick this season, but hadn't appeared in a game since June 1. The Orioles' third-round pick in the 2010 First-Year Player Draft out of UCLA, Klein had a history of shoulder problems while with the Bruins, which is one reason why he fell to Baltimore with the 85th overall pick.
Klein helped lead UCLA to two NCAA Regionals (2008 and '10), and the right-hander made 39 appearances in 2010, which tied the Bruins' single-season appearance record and also tied for the Pac-10 lead in appearances with Arizona State's Mitchell Lambson. Serving as UCLA's closer, Klein notched 10 saves in 2010, the second-highest single-season total in program history and the third-most saves among Pac-10 pitchers that year.