Jimmy Johnson is concerned about the Miami Dolphins' depth at quarterback. His team's suspect running game is starting to come around, though.

Rookie John Avery's two-touchdown performance in his Dolphins debut, a 21-20 victory over San Francisco on Sunday, was an encouraging sign for Johnson.Avery, the Dolphins' first-round pick out of Mississippi, missed the first two exhibitions with a hamstring strain, but showed no ill effects from the injury in an impressive debut. He rushed for 99 yards on 13 carries, including touchdown runs of 2 and 71 yards in the second half.

Miami remained unbeaten in three preseason games. A botched extra point by San Francisco (2-2) was the difference.

Dan Marino, who was 12-of-23 for 158 yards and a touchdown in a little over a half of play, said Avery should give the Dolphins a boost.

49ers coach Steve Mariucci was pretty happy with what he saw from Steve Young and Terrell Owens. They teamed for three touchdowns. He couldn't say the same for his backup quarterbacks. Jim Druckenmiller threw an interception preceding Avery's first touchdown run and Ty Detmer also had trouble moving the team.

No decision has been made on which one will be the top backup to Young, who completed 13 of 21 for 232 yards, including scoring passes of 72, 1 and 26 yards to Owens.

Young's last throw, his third scoring pass to Owens early in the third quarter, left him hurting when his hand struck defensive end Trace Armstrong's helmet on the follow-through.

He trotted off the field grimacing and holding his left wrist and watched the rest of the game from the sidelines with his hand wrapped in a bandage. But Young said afterward the injury wasn't serious.

BENGALS: After getting the job done in two exhibition games, Neil O'Donnell got the job as the No. 1 quarterback for the Cincinnati Bengals.

"I am starting to get a feel for (the receivers)," said O'Donnell, who was named the Bengals' top quarterback by coach Bruce Coslet on Sunday.

O'Donnell completed 15 of 18 passes for 147 yards Saturday, including a 40-yard touchdown pass to Darnay Scott, as the Bengals beat Detroit 33-19. In his last two games, O'Donnell is 20-of-23 without an interception.

"That's a tremendous percentage of completions," Coslet said.

O'Donnell also scrambled three times for 13 yards and was sacked only one time.

"He played well," Coslet said. "The thing that was most noticeable to me is that he had some nice escapes. This group (the Lions) is a twisting, looping, problem-creating defensive line. A couple times it broke down and Neil got out of there, and I wasn't too sure that he could do that effectively, and he showed me that he did."

COWBOYS: Dallas finally got some production from its first-string offense, even though the Cowboys lost their third straight exhibition game.

Emmitt Smith, held back by elbow and thigh injuries in the preseason, ran for 110 yards and a touchdown in the first half of the Cowboys' 22-14 loss to St. Louis on Saturday.

CARDINALS: Although two more Arizona starters were injured over the weekend, the team's general trend is toward better health.

Coach Vince Tobin said Sunday that several key players who have missed significant practice time are on the verge of returning: wide receiver Anthony Edwards (knee), offensive linemen Jerome Daniels (knee) and Anthony Clement (knee) and cornerback Tom Knight (shoulder).

STEELERS: Pittsburgh coach Bill Cowher will have to reshuffle his offensive line again.

Right tackle Chris Conrad, a rookie who unexpectedly became a starter last week after moving from left tackle, injured a ligament in his right knee.