Saints RB C.J. Spiller has knee surgery, expected back for opener

New Orleans Saints running back C.J. Spiller underwent arthroscopic knee surgery Friday but is expected to be back for the team's regular-season opener, a source told ESPN's Adam Schefter and Mike Triplett.

Spiller's injury first surfaced a week ago when he missed the Saints' scrimmage. A source said at the time that it was just a day of rest, and Spiller returned to practice in a limited capacity earlier this week. However, Spiller was absent from practice Tuesday and was held out of the preseason opener at Baltimore on Thursday.

It's unclear if Spiller suffered a setback or if he and the team felt a clean-up surgery would be a better choice in the long term.Saints coach Sean Payton didn't comment on Spiller's injury status after practice Saturday.

The Saints can absorb Spiller's loss in the short term, even if it bleeds into September, since they still have excellent running back depth withMark IngramandKhiry Robinson, among others.

But they are counting on Spiller to play a big role this year in an offense that lost tight endJimmy Graham, receiverKenny Stillsand pass-catching running backs Pierre Thomas andTravaris Cadet.

The Saints signed Spiller to a four-year, $16 million contract in free agency in hopes of adding a big-play dimension that was lacking in 2014 after they traded away runner/receiverDarren Sproles. Spiller, 28, is expected tobecome a big part of New Orleans' passing attack.

Spiller, who spent his first five seasons with theBuffalo Bills, also missed the last seven games of the 2014 season with a broken collarbone. He doesn't have a history of knee injuries, but he did miss part of one game with aknee issue in 2013. Spiller missed a total of only three games due to injury in his first 4 seasons before breaking his collarbone.