Defensive tackle Justin Smith will require three months of rehabilitation after undergoing surgery this week to repair a partially torn triceps, a league source told on Monday. Smith, a four-time Pro Bowl selection, sustained approximately a 50-percent tear of his left triceps on Dec. 16 against the New England Patriots. He missed the final 2 1/2 regular season games. He returned to action for the 49ers' three playoff games. Smith wore a brace on his left arm and played 89.7 percent of the team's defensive plays in the postseason. Smith, who is scheduled to make $8 million in the final year of his contract, could be ready to participate in the final stages of the 49ers' offseason program. He is expected to make a full recovery in time for the opening of training camp in late-July.