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The 49ers are getting to know their fourth offensive coordinator in as many seasons. Head coach Mike Nolan needs Mike Martz to revive an offense that appeared to hit rock bottom last season.

The organization that brought fans Joe Montana and Jerry Rice is trying to win with QB Alex Smith and 35-year-old WR Isaac Bruce.

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One key this season could be whether the offensive line bounces back from a disappointing 2007. The 49ers again think they have the talent up front to become competitive. But depth at tackle is a concern, and guard Larry Allen was good enough to start last season even though his game had slipped. (He's since retired.) The emphasis will remain on Smith and Martz, but their jobs depend on the line's performing closer to expectations.

What we learned from minicamp

The 49ers are serious about finding ways for newly acquired defensive end Justin Smith to maximize his value to the team. Smith, signed to a lucrative free-agent contract after seven seasons with the Cincinnati Bengals, could play outside linebacker in San Francisco. He spent significant time there during minicamp, working on the right side.

Nolan and defensive coordinator Greg Manusky run a 3-4 base defense. They need their defensive ends to occupy blockers and hold up against the run. Smith has the motor to do just about anything the 49ers ask of him. But with a fat contract and a relatively slim waistline, the 275-pound Smith could provide more value in space. He might have a better shot at pumping up his recent modest sack numbers.

Still unresolved

The 49ers haven't formally committed to Smith as their starting quarterback, but it's difficult to imagine them going in another direction. Every quarterback drafted first overall since at least 1967 has started in his fourth season. Giving up on Smith, the top player chosen in 2005, would make little sense given how much the 49ers have invested in him.

The more compelling intrigue during minicamp was at receiver. Incumbent starter Arnaz Battle, listed behind free-agent newcomer Isaac Bruce on the current depth chart, said he neglected to inform the team of plans to miss the first week of practices for personal reasons. The camp was voluntary, of course, but the 49ers might be better off if key players did all they could to master Martz's offense.

Bruce participated in the first week of practices as a favor to the coaching staff. He skipped the second week because, at 35, he doesn't do voluntary camps. Bruce knows Martz's offense, but he won't get extended work with Smith or the other quarterbacks until training camp.

Injury analysis

Smith took part in practices and was able to throw deep after rehabbing from surgery on his separated throwing shoulder. The team talked about limiting Smith's deep throws as a precaution, but Smith appeared to perform without significant limitations. Offseason practices are perfect for Smith because teams prohibit defenders from making contact with quarterbacks. A truer test for Smith will come once the 49ers put on the pads and play exhibition games.

Linebacker Manny Lawson's return from season-ending knee surgery could give the defense a boost at a position of strength. Lawson was playing well before suffering a torn anterior cruciate ligament injury two games into last season. A first-round choice in 2006, Lawson figures to start on the strong side. The 49ers have limited his on-field work during minicamp.

Starting guard David Baas remains sidelined by a torn pectoral suffered in April. Baas could miss part or all of training camp. Starting safety Mark Roman also underwent surgery this offseason. His shoulder should be ready for training camp.

Tracking Gore, Davis

Martz's arrival and Smith's future are commanding significant attention. Their working relationship is critical for the 49ers after Smith clashed openly with Nolan. But two other guys also will help determine whether this offense will bounce back.

Running back Frank Gore and tight end Vernon Davis might be the 49ers' best players on offense. Martz generally has not featured tight ends as receivers, but Davis has the athletic ability to beat linebackers, safeties or anyone else he might encounter.

Gore and Davis put up admirable numbers last season while the rest of the offense tanked. Davis is a top-notch blocker coming off perhaps the quietest 52-catch season a tight end has ever had. Gore rushed for 1,102 yards with a 4.2-yard average. He also caught 53 passes. Those numbers should improve with Martz in command.

Training camp start date: July 24

Mike Sando covers the NFL for ESPN.com.