Unless something unforeseen happens in the next two weeks, there won't be any major surprises when the 49ers trim their roster to 53 players. None of the position battles still ongoing or roster spots up for grabs will significantly alter the makeup of the team.

Here are a few notable players whose jobs are in jeopardy:

• Josh Johnson (QB, fifth year, played for Jim Harbaugh in college) -- After spending four years with Tampa Bay, Johnson sought out the 49ers and a reunion with Harbaugh. He's listed at No. 3 on the depth chart, but is in a battle for the No. 3 job with second-year pro Scott Tolzien. He's the most experienced of the potential backups with five NFL starts and 26 appearances in his career.

• Anthony Dixon (RB, third year, 2010 sixth-round draft pick) -- Dixon's role with the team took a significant step back last year after the team drafted Kendall Hunter in the fourth round. Dixon's carries went from 70 as a rookie to 29 in his second year and was he was largely ineffective in short-yardage situations, where he was primarily used on offense. With the addition of short-yardage RB Brandon Jacobs, second-round pick LaMichael James and special teams standout Rock Cartwright, Dixon's roster spot is jeopardy. OC Greg Roman said Dixon's performance in the team's second preseason game against Houston was one of his best games since the new staff arrived prior to last season. Even if he turns in a similar performance against the Broncos Sunday, it probably won't be enough to keep him with the team.

• Tramaine Brock (CB, third year, undrafted rookie free agent 2010) -- It was a little over a year ago when Brock left training camp as the team's No. 3 CB and validated his spot on the depth chart with interceptions in the first two games of the year. He played two more games, then missed three with a hand injury, which allowed rookie Chris Culliver to step in and impress the coaching staff. Brock didn't make a tackle the rest of the regular season and only saw extended playing in the NFC Championship game due to an injury to Tarell Brown. With the addition of Perrish Cox, Brock's role figures to decrease again this year -- if he makes the team.

Follow 49ers reporter Kyle Bonagura on Twitter: @CBSSportsNFLSF and @KyleBonagura