No serious injury for Ray McDonald

SANTA CLARA, Calif. -- The San Francisco 49ers appear to have avoided another serious injury on defense.

Coach Jim Harbaugh told San Francisco radio station KNBR on Tuesday it appears defensive tackle Ray McDonald -- injured during a 34-3 win Sunday night over the Houston Texans -- "might have walked one off."

McDonald, who left the game with a right biceps injury, said he was worried when he felt a sting. McDonald told reporters Tuesday that his bicep is partially torn and he will likely have surgery after the season. However, he is expected to be able to play through the injury.

Harbaugh said MRI results brought positive news.

"We dodged a bullet there," Harbaugh told the radio station. "It looks like Ray might have walked one off."

The 49ers need McDonald, especially now. Patrick Willis has missed the past two games because of a groin injury, and fellow Pro Bowl linebacker Aldon Smith remains away from the team while he receives treatment for substance abuse.

Harbaugh said Monday he has exchanged a few texts with Smith. He also said the reports the team is getting on Smith are positive but that there is no timetable for his return.

Barring a setback, Willis could play Sunday against the Arizona Cardinals. It would not be a surprise if McDonald misses some practice time this week as a precaution, but it looks like he will be able to play as well.