Maatta underwent a shoulder procedure at the Cleveland Clinic and will miss 4-6 months. The 19-year-old played 78 games for the Penguins this season, finishing with nine goals and 20 assists. He added four assists in Pittsburgh's run to the Eastern Conference semifinals.
Bennett had wrist surgery will need at least four months to recover. Bennett missed a significant chunk of the season with wrist issues and finished with three goals and four assists in 21 games.
The procedures came a day after defenseman prospect Derrick Pouliot underwent labral repair surgery. Pouliot, Pittsburgh's first-round pick in the 2012 NHL draft, will miss at least four months.