Browns quarterback Johnny Manziel has been throwing tennis and weighted balls as he recovers from a sore right elbow.

Coach Mike Pettine said Manziel is "on schedule" in his rehab program and that he could begin throwing a football again as early as Friday. Manziel has been dealing with tendinitis in his forearm and elbow, a condition that has bothered him since his freshman year at Texas A&M.

Manziel hasn't thrown a football since Aug. 11 and the Browns sat him in their final two exhibitions. There's a chance Manziel may not be ready for the Sept. 13 season opener. Thad Lewis has moved ahead of Manziel as the backup to starter Josh McCown.

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Pettine said the team has not yet decided if it will keep three quarterbacks on the 53-man roster.