SAN FRANCISCO (AP) -- J.J. Stokes has a hard time explaining it.

Sure, Steve Young and Garrison Hearst, two of the key elements in the San Francisco 49ers' explosive attack last year, remain sidelined indefinitely this season by injuries.

Yet, the vanishing act of Stokes, Jerry Rice, and Terrell Owens has dragged down San Francisco's once dominant offense even more. The 49ers (3-4) will be trying to snap their first three-game losing streak since 1980 when they play the Pittsburgh Steelers (4-3) on Sunday.

They'll be trying to do that with an offense ranked in the bottom third of the league against a Pittsburgh defense that hasn't allowed a touchdown in three of its seven games and preserved the Steelers' 13-9 win over Atlanta two weeks ago with two goal-line stands in late going.

"It's weird," Stokes said. "I look back at last year when we were so effective and everything was just clicking. Right now, it just seems like we have one or two things clicking and not quite everything is on the same page."

To be fair to Jeff Garcia, who is making his fifth career start since Young was sidelined by a major concussion on Sept. 27, San Francisco's lackluster offense was a problem from the start. Young, whose career passer rating of 96.8 is the highest in NFL history, had slipped to 60.9 before being injured.

The ineffective play of the wide receivers is especially troubling because they were supposed to rival Minnesota's threesome of Randy Moss, Cris Carter and Jake Reed as the best in the league. But the 49ers' trio hasn't come close.

Owens has missed the past two games with an ankle sprain but he's expected to play this week. Rice has a team-high 30 catches but his 9.8-yard average per catch is well below his career average of 15.5. A 35-yard reception by Stokes is the longest by a San Francisco wide receiver this season.

Pittsburgh coach Bill Cowher said opposing defenses could be taking San Francisco's receivers out of the mix by taking advantage of Garcia's inexperience.

"They've been disruptive with their coverages that they've shown to Jeff, and he's maybe in the process of seeing a lot of this stuff for the first time," Cowher said. "It's a very quick rhythm passing game, so if you can put some indecision into the reads of the quarterback, it can be disruptive. And that's the challenge we're faced with this week."

San Francisco coach Steve Mariucci said the 49ers have lacked the big play, including the trademark runs after catches by the wide receivers.

"Geez, last year, we threw a 1-yard hitch to Terrell Owens and he went 72 yards with it for a touchdown," Mariucci said. "Those types of play occur sometimes when you least expect it, because of a missed tackle or great run or whatever.

"We haven't had them. Some of it is protection reasons. Some of it is a new quarterback. Maybe we're trying to throw shorter instead of intermediate passes. Hopefully, those type of throws will come as we improve here."

Both teams head into the game off their bye.

Stokes said he hopes the 49ers run more intermediate and deep pass routes and perhaps even throw from a shotgun formation, which hasn't been used in San Francisco for some 20 years but is a familiar system to Garcia. The 49ers toyed with the scheme during portions of their practices the last two weeks.

"I think it could definitely be beneficial," Stokes said. "It could possibly give Jeff some time to sit back there. He can just scan the field and get the ball to the open receiver."

Stokes also said San Francisco has to do a better job of mixing in varied pass routes. Right now, the 49ers run predominantly short routes and defenders are attacking San Francisco receivers from the time they get to the line of scrimmage.

Even if the 49ers improve offensively, they have to hope their defense shuts somebody down.

Though Pittsburgh's offense also has been mediocre and Kordell Stewart has struggled under offensive coordinator Kevin Gilbride, his third coordinator in three years, the Steelers could be primed for a breakout against the 49ers. San Francisco ranks last in the league in pass defense and second-to-the-last in points allowed.

"I guess it's their weakness against our weakness," Steelers running back Jerome Bettis said.

Bettis added the Steelers are getting more comfortable with Gilbride's system.

"When we execute right, we're going up and down the field," he said. "We feel good about it. It's just a matter of us executing and getting in that rhythm and staying there."

PITTSBURGH Season schedule and results

SAN FRANCISCO Season schedule and results

September 12 @Cleveland W 43-0 September 19 @Baltimore W 23-20 September 26 Seattle L 10-29 October 3 Jacksonville L 3-17 October 10 @Buffalo L 21-24 October 17 @Cincinnati W 17-3 October 25 Atlanta W 13-9 November 7 @San Francisco 4:15pm ET November 14 Cleveland 1:00pm ET November 21 @Tennessee 1:00pm ET November 28 Cincinnati 1:00pm ET December 2 @Jacksonville 8:20pm ET December 12 Baltimore 1:00pm ET December 18 @Kansas City 12:40pm ET December 26 Carolina 1:00pm ET January 2 Tennessee 4:15pm ET

September 12 @Jacksonville L 3-41 September 19 New Orleans W 28-21 September 27 @Arizona W 24-10 October 3 Tennessee W 24-22 October 10 @St. Louis L 20-42 October 17 Carolina L 29-31 October 24 @Minnesota L 16-40 November 7 Pittsburgh 4:15pm ET November 14 @New Orleans 1:00pm ET November 21 St. Louis 4:15pm ET November 29 Green Bay 9:00pm ET December 5 @Cincinnati 1:00pm ET December 12 Atlanta 4:15pm ET December 18 @Carolina 4:15pm ET December 26 Washington 8:20pm ET January 3 @Atlanta 9:00pm ET

Records source: STATS, Inc.

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