OAKLAND – Rookie wide receiver Josh Morgan of the 49ers showed Friday night he can be just as impressive on the playing field as he's been on the practice field.

Against the Raiders, the sixth-round draft pick led all receivers with four catches for 68 yards, all of them from starting quarterback J.T. O'Sullivan.

Coaches and evaluators have been pleasantly surprised by how quickly the 219-pound wideout has digested Mike Martz's hefty playbook, and he hasn't been affected by the dropped passes he sometimes struggled with at Virginia Tech.

The 49ers keep track of all practice receptions. Morgan is second on the team this summer to veteran Bryant Johnson.

Veteran observers – Wide receiver Isaac Bruce, whose veteran status allows him to practice sporadically at training camp, did not play, making Arnaz Battle and Morgan the starters at receiver. Running back Frank Gore, meanwhile, ran twice for six yards before giving way to DeShaun Foster.

Dashon Goldson started in place of Mark Roman (hamstring) at free safety. With Roman out, fellow safety Michael Lewis was wired with the radio receiver for the defense. Safety Keith Lewis took over radio duties when the defensive starters left in the first half.

Karma chameleons – So much for the 49ers being a 3-4 defensive team. San Francisco opened the game in a 4-3 front.

The 49ers' top free-agent acquisition, Justin Smith, was at left defensive end. Isaac Sopoaga and Aubrayo Franklin were at defensive tackle, and Ray McDonald was at right defensive end. On the next play, Smith stood next to McDonald and played right outside linebacker.

49ers' injuries – The 49ers' injured players were center Eric Heitmann (hip), offensive tackle Damane Duckett (knee), return man Allen Rossum (knee) and tight end Delanie Walker (cut on elbow). None of the injuries was considered serious.

Raiders sign kicker – Before the game, the Raiders signed kicker Aaron Elling, who handled duties in place of Sebastian Janikowski, who did not dress.

Elling has been a regular kicker once, for Minnesota in 2003. He was released by Cincinnati last September after he tore a knee ligament during an exhibition game.

Janikowski injured his left leg in practice Wednesday. Coach Lane Kiffin said it's not considered serious and hopes Janikowski can kick Friday at Tennessee.

To make room for Elling, the Raiders waived injured offensive lineman Mark Wilson, who broke his leg during special-teams practice in training camp.

Wide receiver Ronald Curry (hamstring) came out for warmups but was pulled when the leg started to bother him.

Another regular, linebacker Ricky Brown, did not play. Robert Thomas started for Brown.

Rookie wide receiver Arman Shields (knee), safety Greg Wesley (back) and linebacker Grant Irons (hamstring) also did not suit up.

Rookie safety Tyvon Branch left the game with an injured thumb he hit on a helmet. He had a cast put on it and returned to the game. Kiffin said Branch would need surgery but could still play.

Returning for seconds – Raiders wide receiver Johnnie Lee Higgins returned a punt 53 yards for a second-quarter touchdown.

Last year as a rookie, Higgins returned a kickoff and punt for a touchdown during the exhibition season.

Higgins didn't have that kind of success in the regular season. He had only 20 returns for 103 yards and lost his job as the punt returner for part of the season because of fumbling problems.

Getting familiar – The Raiders will return to McAfee Coliseum at noon Sunday for the Raider Nation Celebration. The team will hold a practice as part of the day. Admission is free.

Read Matthew Barrows' 49ers blog at www.sacbee.com/blogs.