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DAVIE, Fla. -- At age 24 and a year out of college, Ronnie Brown has landed his first full-time job.

The Miami Dolphins hope he's up to it.

Long accustomed to sharing carries with someone named Williams -- Cadillac at Auburn, then Ricky last season in Miami -- Brown is poised to become a workhorse running back in his second NFL season.

"It's an opportunity," he said. "I welcome the challenge and look forward to it."

Ricky Williams' one-year suspension means the majority of handoffs will likely go to Brown, and what he does with them could prove pivotal to the Dolphins' success.

They've started training camp hoping to end a four-year playoff drought, and optimism is high in the wake of six consecutive wins to end last season and a blockbuster trade to acquire quarterback Daunte Culpepper.

But Brown's durability ranks among the team's biggest question marks, if only because he has never assumed a full load.

His one-season high at Auburn was 175 attempts as a sophomore, and as a rookie with Miami last season he had 207 -- an average of less that 14 per game. This year, he might often reach that figure by halftime.

Brown's one-game high in 2005 was 23 carries. Ricky Williams has topped that total 32 times.

"It's going to be different," Dolphins defensive end David Bowens said. "The workload is going to be a lot, especially in the NFL.

"I think Ronnie has the confidence to do that. Ronnie's ego has been up there since I've known him. His swagger, the way he carries himself -- most first-round picks are like that."

Coach Nick Saban selected Brown with the second pick in the 2005 draft, then signed him to a five-year contract with $20 million guaranteed. The investment suggests the Dolphins projected Brown to become a full-time back, knowing better than to count on the mercurial Ricky Williams for a long-term contribution.

When Williams was suspended in April for his fourth violation of the NFL drug policy, Miami shopped to upgrade depth at running back but came away empty. Veterans Sammy Morris and Travis Minor return as backups, ensuring that Brown will stay busy as long as he stays healthy.

At 6 feet and 232 pounds, he appears sturdy enough to carry a heavy load, and he showed a penchant for running over tacklers last year. He ranked second to former college teammate Cadillac Williams among NFL rookies with 907 yards rushing, and he added 232 yards on 32 receptions.

Brown said he reported to camp in better shape and more confident than a year ago, eager to improve on his 2005 performance.

"Hopefully there's a big difference," he said.

He figures he's already ahead of his pace last year, when he missed the first three weeks of camp in a contract holdout and struggled to catch up.

"As a rookie, you come in and your head is swimming," Brown said.

Now he can draw on a year of NFL experience. He studied film during the offseason and decided he spent too much time trying to fake out defenders.

"I looked at some of the mistakes I made and the things I needed to work on," he said. "On this level, guys are a little faster, so when you make that initial move, you need to stick with it."

Beginning Sept. 7 at Pittsburgh, Brown will get plenty of chances to show what he has learned.

Copyright 2006 by The Associated Press

This story is from ESPN.com's automated news wire. Wire index