SANTA CLARA, Calif. — Alex Smith and Michael Crabtree walked together step for step through the San Francisco 49ers' locker room Tuesday after the completion of two days of organized team activity practices.

It's the kind of unity that's developing rapidly between the team's starting quarterback and the talented young wide receiver.

Their rapport was even more apparent on the field during the previous two practices. The 49ers began 11-on-11 team drills Monday with Smith completing passes to Crabtree on each of the team's first four plays, and that connection continued throughout the two days.

"The more we work together, the better we get," Crabtree said Tuesday. "We still have a long ways to go, but this offseason we're going to put the icing on the cake."

The 49ers have not had a legitimate No. 1 wide receiver since Terrell Owens left the team after the 2003 season. But Crabtree, the team's heralded 2009 first-round draft pick, is making quick progress toward becoming San Francisco's new go-to guy.

After missing all of training camp and the first five games last season due to a contract stalemate, Crabtree was in San Francisco's starting lineup a week later for his NFL debut and was the team's most productive wideout by the end of his rookie year.

Crabtree finished his first season with 48 receptions for 625 yards and a 13.0-yard average.

His reception and yardage totals each were the fourth-best in franchise history for a rookie wideout, and his 56.8 yards receiving per game led all NFL rookie receivers.

Crabtree's quick growth has carried over to the beginning of spring workouts, where he has become a central figure in the team's passing attack.

"This is really kind of the start of it all," Smith said. "It's nice to have Crab in this time of year and be able to really be on the same page and have that communication, to be able to trust that we're going to be seeing the same thing, reacting to it, and we're both making the same adjustments and those types of things. There's a lot to look forward to."

Crabtree is looking forward to having an entire offseason to work with the team and learn his craft. He wasn't allowed at the team facility during his contract impasse last year, missing 57 practices, four exhibition games and four regular-season games before finally joining the 49ers on Oct. 7. He then sat out San Francisco's Oct. 11 game against Atlanta before getting on the field.

He's making up for lost time this spring. Already entrenched as a starter, Crabtree now is working to take his game to the next level.

"When I first got here last year, it was all about cramming a lot in during a little amount of time," Crabtree said. "Right now, we have the time, and I'm just taking it step by step. Every day I'm going hard trying to learn something new and get better."

Crabtree's style and ability already have made an impression on backup quarterback David Carr, who joined the 49ers as a free agent this month.

"Crab kind of reminds me of the guy I played with in Carolina, Steve Smith," Carr said. "That body frame, able to really control what he's doing with his body, kind of running at the pace that he needs to run at. You never feel like he's out of control when he's running. He knows exactly what he wants to do with his body."

Crabtree's emergence gives the 49ers three young and inviting targets for the team's passers.

Fifth-year veteran Vernon Davis made the Pro Bowl last season after tying an NFL record for tight ends with 13 touchdown receptions, and third-year pro Josh Morgan led the team's wideouts with 52 receptions while settling in nicely as the starter opposite Crabtree.

But as Crabtree continues to catch on quickly, it appears his best is yet to come.

"I'm working hard to be a big part of this offense, and I even take my playbook to bed," Crabtree said. "Me and Alex are really going to get it in this offseason. We've got a lot of things ahead of us."

NOTES: Also Tuesday, San Francisco signed free agent kicker Shane Andrus to a one-year deal. Andrus joined the 49ers for the final game last season and converted all four of his point-after attempts Jan. 3 at St. Louis.