Josh Johnson has no idea how much he'll play behind 49ers starter Alex Smith, or if the backup job is even his to earn ahead of second-year pro Colin Kaepernick.

He isn't too worried about his role just yet.

For now, Johnson is thrilled to be reunited with reigning NFL Coach of the Year Jim Harbaugh, his former college coach who took a chance on the undersized quarterback at the University of San Diego. Harbaugh developed the 5-foot-11, 145-pound Oakland Tech prep star into a record-setting QB in Southern California.

The 49ers now have four quarterbacks on the roster, which Johnson insists isn't a big deal. Smith signed a three-year contract Wednesday, a day after Peyton Manning was formally introduced by the Denver Broncos. The 49ers had been among the finalists to land the four-time NFL MVP.

"I've been in worse situations. I've been in camps where there were five guys," Johnson said. "It's about taking advantage of the opportunity that you get."

He played his first career game of racquetball with Harbaugh, Smith and Kaepernick when he met with the team Thursday. Johnson visited the Redskins on Wednesday.

The familiarity with Harbaugh was a huge draw to the Bay Area — not to mention being part of a turnaround that began with the team's run to the NFC championship game last season in Harbaugh's first year.

"My college career told me, 'Look at what I did playing for these coaches, playing in this offense. I had tremendous success. We won so many games. We accomplished so much as a team and changed so much for San Diego," Johnson said. "Why not do that in the pros as well, to grow up in the pros under the same coaching staff? (Harbaugh) showed me how to trust in all my abilities. Coming out of high school, my body was still developing so I kind of doubted myself. He showed me how to play the quarterback position with confidence and to be precise with everything."

The 25-year-old Johnson started five games in four seasons with Tampa Bay. He completed 96 of 177 passes for 1,042 yards, five touchdowns and 10 interceptions in 26 career appearances.

He believes he will continue to get better under Harbaugh. So far, they haven't even discussed where Johnson fits in — and he is perfectly fine being patient and paying his dues. Scott Tolzien is the other quarterback on the roster.

"I didn't get into the specifics. It wasn't necessary," Johnson said. "As a quarterback, there's one guy out there and it's about reps. I was told I'd get an opportunity to continue to develop. ... They had a great year last year and I know the success will continue because I've played for this coaching staff already. I know what they expect out of their players, details that go into the preparation every week. They put their pla