Outside linebacker Ahmad Brooks says a friendly competition has emerged among the 49ers’ second-ranked run defense: Which side is better at stopping ball carriers?

Brooks and Ray McDonald basically lock down the left flank while Justin Smith, Aldon Smith and Parys Haralson do the same on the right side.

“Both sides are good,” Brooks said earlier this week. “I can’t downplay Justin Smith, Aldon and Parys. They do a very good job on that side. Nobody runs the ball on them, either.

“But I just think that me and Ray hold it down a little bit more,” Brooks added with a laugh. “It’s cool. It’s all love. It’s fun, man. We’re here to win the Super Bowl. We’re here to get to the playoffs.”

Opponents are gaining 74.7 yards per game on the ground. Coming up Sunday are the visiting Cleveland Browns, who had star running back Peyton Hillis sit out Thursday’s practice because of a hamstring injury that kept him out of Sunday’s win over Seattle.

Defensive coordinator Vic Fangio hasn’t heard any talk — nor does he want to — about an intrateam rivalry regarding the run defense. “That really should not be a competition because many runs can cut back,” Fangio said. “Run defense is team defense.”

Nose tackle Isaac Sopoaga offered this lighthearted take: “I don’t know why (Brooks) would say that. It’s all about the middle. That’s what anchors the defense. They get lucky if a play bounces out. It’s all about the middle.” Also in the 49ers’ middle: potential Pro Bowl linebackers Patrick Willis and NaVorro Bowman.

Both the 49ers and Browns have installed West Coast offenses this season, but Fangio insisted neither those nor any others around the league truly mimic Bill Walsh’s revolutionary system. “All of these self-proclaimed West Coast offenses really are not run in Bill Walsh’s offense,” Fangio said. ” … Everybody’s taking their own version of it and putting their own little mark on it, but to me, I don’t see anybody running the West Coast offense.”

Wide receiver Braylon Edwards (right knee) and center Jonathan Goodwin (concussion) practiced in limited fashion but are on track to start Sunday. Edwards looks in “pretty darn good condition physically,” according to offensive coordinator Greg Roman. Goodwin has worn a black jersey in practice the past two days to minimize his contact.

Fullback Moran Norris returned to practice, albeit in limited capacity, for the first time since sustaining a broken left lower fibula against the Dallas Cowboys in Week 2. Bruce Miller remains the leading candidate to start at fullback until Norris proves healthy enough to compete for that spot.

Cornerback Tramaine Brock practiced for the first time without a cast on his previously broken left hand.

Cornerback Chris Culliver was limited in practice with a shoulder injury, but Fangio still has Culliver slotted as his No. 3 cornerback.

Haralson (hamstring) and guard Adam Snyder (stinger) have both fully practiced the past two days after suffering injuries that forced them out of the Oct. 16 win at Detroit.