Pitta, who signed a $2 million second-round tender in May, suffered the injury Saturday during a training camp collision with safety James Ihedigbo.
The fourth-year tight end underwent surgery late Saturday and is also thought to have sustained a fractured hip in the collision, Baltimore Coach John Harbaugh said.
Pitta was coming off an excellent 2012 season for the Super Bowl champions, during which he grabbed a career-high 61 catches for 669 yards and seven touchdowns.
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