The season hasn't even started yet and already the Miami Dolphins are dealing with injuries to players expected to play key offensive roles.

Pro Bowl center Mike Pouncey underwent hip surgery Monday and is expected to miss at least three months, sources familiar with the injury said. Meanwhile, running back Knowshon Moreno will undergo arthroscopic knee surgery this week and miss four to five weeks, sources said.

The Dolphins hope to have Moreno back in time for the start of the preseason, but Pouncey is expected to be sidelined for the start of the regular season. Moreno signed a $3.275 million, one-year contract in March.

Pouncey also faces a possible suspension from the NFL. He's the only player implicated in last year's bullying scandal still on the Dolphins' roster.

Pouncey tore the labrum in his hip sometime during the Dolphins' offseason workouts. His absence will shake up a Miami offensive line that was transformed this offseason. The 6-foot-5, 305-pound Pouncey was the lone returning starter on the unit, the leader of the line and arguably Miami's best offensive player.

With Pouncey out, the Dolphins will be faced with a quandary at center. Undrafted free agent Sam Brenner is Pouncey's backup, though Miami also could opt to try another lineman at center. Former Rams guard Shelley Smith also can play center. But on opening weekend, Miami will have five new starters on its offensive line.

Information from The Associated Press was included in this report.