SAN DIEGO - On a day when they otherwise would have played Brigham Young, receiver Roberto Wallace and the San Diego State football team returned to practicing outdoors on Saturday.

For Wallace, who grew up playing soccer in Panama, every pass pattern in practice or a game is another step toward becoming proficient in the game called American football in Panama.

"It's harder than I thought, but I've been here three years and I played two years in high school," Wallace said. "That's long enough; there are no excuses for me anymore."

The Aztecs were on the practice field instead of at Qualcomm Stadium after their game against BYU was postponed until Dec. 1 because of the wildfires that ravaged San Diego County last week.

Wallace, a redshirt sophomore from Oceanside High, was a last-minute replacement in the starting lineup for Darren Mougey in the Aztecs' 20-17 last-minute loss to New Mexico last week. The 6-foot-4, 210-pounder responded with three catches for 20 yards.

"He was a raw player coming out of high school, but we still believe he has great upside here," San Diego State coach Chuck Long said. "Within the last year, since spring ball, he has really dedicated himself. He's made the commitment that, 'I don't know this game, and I need to get better.'

"On paper, you draw up that you go out 15 yards and cut. But there are a lot of nuances that go into that 15 yards, coming out of your break and then you attack the football. He didn't know about getting between the zones and feeling when it's man coverage."

Wallace played soccer internationally with the Panama junior national team and never tried football until his junior year at Oceanside in 2003.

He was born in Panama but attended an American school on a U.S. Army base where his father, retired from the Army, worked as a civilian. When his father's job was transferred to Puerto Rico, he came to Oceanside in 2002 to live with an aunt.

With size and speed to dominate high school athletes, he came to the Aztecs ranked as one of the top 50 receivers in the nation. But then the reality of learning the game against other scholarship athletes was complicated by injuries in his first two years, including shoulder surgery that ended his chances to play in 2006.

"I surprised myself against New Mexico, and I think I can do some things at San Diego State," Wallace said. "I don't want to be just another receiver. I want to be a receiver people talk about."