Lakers' Steve Blake out 3-4 weeks

EL SEGUNDO, Calif. -- It was two steps forward and one step back for the Los Angeles Lakers' beleaguered bench on Friday against the Cleveland Cavaliers.

Forwards Josh McRoberts and Troy Murphy re-entered the lineup at the same time Steve Blake is expected to be out 3-4 weeks with a costochondral fracture, which is a fracture of the cartilage connecting the rib to the sternum.

"That thing is at a point to where even if he makes a hard move, it can hurt him or bother him," Lakers coach Mike Brown said of Blake's condition.

Brown's condition was downgraded from day to day Friday after further evaluation of his fracture.

Blake is the Lakers' leading scorer as a substitute, averaging 7.3 points and 2.8 assists in 24.3 minutes per game. He leads the team in 3-pointers made, connecting on 17 in the Lakers' first 12 games.

Brown said rookie guard Darius Morris will assume the majority of Blake's minutes and the coach might also slightly increase Derek Fisher's playing time as the starting point guard.

Morris made his NBA debut Wednesday against the Utah Jazz and registered four points and two assists in 13 minutes.

"The young fella did a nice job [in Utah]," Brown said. "That's a hostile environment with the crowd and all that. It was an intense game and I thought he kept his composure and tried to do what we asked of him and gave us a little bit of a spark."

As for the returning players, McRoberts will solidify Brown's big-man rotation after missing the last six games with a sprained big toe on his left foot and Murphy has recovered from the gastroenteritis that caused him to miss the Lakers' last two games.

Guard Jason Kapono was also available after spending the last two games away from the team to be with his wife, Ashley, and their newborn twin daughters, Isla and Campbell.

Dave McMenamin covers the Lakers for ESPNLosAngeles.com.