WHO'S THE MAN?

J.T. O'Sullivan

49ERS QUARTERBACK

All eyes will be on the former Jesuit High School and UC Davis star who has emerged from six years of obscurity to become the starting QB. O'Sullivan is well-prepared and accurate but must be careful not to be reckless when rattled.

THE PARTICULARS

• Time: 1:15 p.m.

• The line: Cardinals by 2 1/2.

• TV: Ch. 40, Sam Rosen (play-by-play), Tim Ryan (color), Chris Myers (sideline).

• Radio: KFBK (1530 AM), KNBR (1050 AM). Joe Starkey (play-by-play), Gary Plummer (color).

• Why watch? Mike Martz's offense makes its regular-season debut. Martz's system looked sharp during the exhibition season, but players insist the offensive wizard has yet to reveal his full arsenal.

• Rewind: In 2006, the Cardinals swept the season series. Last year, the 49ers returned the favor, posting an ugly 20-17 win in the season opener. The teams played one of the most entertaining games of the season Nov. 25, a game the 49ers won 37-31 in overtime when Tully Banta-Cain pounced on a fumble in the end zone.

49ERS' THREE KEYS

• Perhaps no coach needs a fast start more than Mike Nolan. He has little leeway after three consecutive losing seasons, and he is facing one of the more beatable teams. If Nolan loses early, his typical late-season run won't save his job.

• Frank Gore was quiet in the exhibition season as the 49ers made sure their No. 1 tailback was healthy entering the season. He is, and with an improved offensive line, Gore expects to be at least as productive as he was in 2006.

• The 49ers paid Justin Smith a boatload of money to be the playmaker along their defensive line. Watch for Smith to line up at four positions today and to be the focal point of the team's pass rush.

CARDINALS' THREE KEYS

• For the first time in five years, the Cardinals enter the season without No. 3 wide receiver Bryant Johnson, now a 49er. His former role is being handled by three receivers, although Steve Breaston appears to be the primary option.

• Don't look for Antrel Rolle at his usual cornerback position. The Cardinals moved the former first-round pick to safety in the offseason, and he has reportedly adapted well to his new rolle, er, role.

• The 49ers will have to watch out for linebacker Karlos Dansby and safety Adrian Wilson. The two are arguably the best players on the Arizona defense, and they were effective on delayed blitzes last year against the 49ers.

MATCHUP TO WATCH

49ers tight ends vs. Arizona safeties

Previous incarnations of Mike Martz's offense have relied on wide receivers. This year, Martz will lean almost as heavily on tight ends Vernon Davis and Delanie Walker. Martz believes their combination of size and speed will put extra pressure on opposing secondaries. The Cardinals, however, have two excellent safeties in Antrel Rolle and Adrian Wilson. Rolle, a former cornerback, has good coverage skills, and Wilson is one of the more physical safeties in the league. How well they handle the 49ers' tight ends will be a key part of the game.

INJURY REPORT

49ers

Doubtful: QB Alex Smith (shoulder). Probable: NT Aubrayo Franklin (knee), LB Parys Haralson (shoulder), S Michael Lewis (back) and TE Delanie Walker (calf).

Cardinals

Doubtful: DT Gabe Watson (knee), DT Alan Branch (knee). Questionable: TE Jerame Tuman (hamstring). Probable: TE Ben Patrick (ankle), T Mike Gandy (knee).