Upon Further Review: San Francisco 49ers

SANTA CLARA, Calif. -- An examination of four hot issues from the San Francisco 49ers' 34-3 win against the Texans:

Another defensive injury: The 49ers defense might have suffered another key loss as defensive tackle Ray McDonald went out with a right biceps injury. McDonald said after the game that he felt a sting. He will have an MRI on Monday. Tony Jerod-Eddie replaced McDonald. The 49ers defense has suffered several injuries, playing the past two games without All-Pro linebackers Aldon Smith (receiving treatment for alcohol abuse) and Patrick Willis (groin). San Francisco has been dominant without the two stars, allowing a combined 14 points. Now, the 49ers might have to adjust again if McDonald is out.

Brock shines: Tramaine Brock is one of the many depth players who is getting an opportunity on defense, and he is cashing in. On the third offensive play of the game Sunday, Brock returned an interception 18 yards for a touchdown. It was the first of his two interceptions in the game. Brock took over as the No. 3 cornerback last week when Nnamdi Asomugha went out with a knee injury. He played well against the Rams. Now, it is highly unlikely Asomugha gets his job back. It will be interesting what the 49ers do with a 32-year-old fourth cornerback. Right now, the focus is on Brock.

Kaepernick manages game: OK, so the 49ers scored 34 points and quarterback Colin Kaepernick completed only six passes. But it didn’t matter. The 49ers dominated this game. There is no denying the 49ers aren’t getting much help in the receiving game from anyone other than Anquan Boldin and Vernon Davis. But until Mario Manningham and Michael Crabtree return, the 49ers are going to have to be conservative in the passing game. Kaepernick will not have Josh Freeman as his backup. The former Tampa Bay starter has agreed to terms with the Vikings. The 49ers reportedly talked to Freeman. It’s no surprise. The 49ers like quarterbacks, and Freeman would have been an upgrade as a backup over Colt McCoy and newly signed John Skelton. But Freeman’s road to playing is shorter in Minnesota.

Run game sets tone again: The San Francisco run game continued to shine against Houston. The 49ers called a designed run play on 67.3 percent of their plays Sunday, according to ESPN Stats & Information. Why not? It was working -- the 49ers had 118 of their 177 rushing yards before contact.