The operation was performed on Monday.
The injury occurred in Sunday's game against Cleveland, when Pitta went down without being touched and had to be removed from the field on a cart.
It's the same injury that sidelined Pitta for much of last season.
Coach John Harbaugh is unsure if it's a career-ending injury. He says, ''We have to be really hopeful for Dennis' return. I'm sure we'll learn about that in the coming weeks.''
Harbaugh acknowledged that the team is also looking for another tight end.
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