By Scott Garbarini, NFL Editor

(Sports Network) - Still shaking off the rust from a long injury-induced absence, Peyton Manning hopes to take another step forward in his comeback when the new Denver Broncos quarterback leads his team into a preseason battle with the San Francisco 49ers at Sports Authority Field.

Manning's health hasn't been an issue during training camp as the coveted free-agent acquisition continues his recovery from multiple neck surgeries that kept him out all of the 2011 season. The four-time NFL Most Valuable Player played the entire first half of last week's matchup with Seattle without incident, though the two interceptions he threw in the Broncos' 30-10 loss suggests his timing isn't quite there just yet.

The 36-year-old's overall performance was certainly encouraging, however. Manning completed 16 of his 23 attempts on the night and amassed 177 yards before exiting.

It was his first appearance at Sports Authority Field since choosing the Broncos over several other suitors, including the 49ers, shortly after being released by Indianapolis in March.

An improved effort may be tough to come by on Sunday, however, considering the 49ers return all 11 starters from a defense that yielded the second-fewest points and the fourth-fewest total yards during the team's 2011 turnaround. Houston's Matt Schaub did find some success in last weekend's preseason clash with San Francisco, though, with the veteran hitting on 11-of-14 throws for 128 yards and a touchdown to help the Texans to a 17-9 win.

The Broncos will get back a potential weapon for Manning this week, with rookie running back Ronnie Hillman set to make his belated pro debut after sitting out the first two contests with a hamstring strain.

Denver's defense is expected to have a few more healthy bodies added to the mix as well. Cornerback Tracy Porter (illness) and rookie linebacker Danny Trevathan (ankle) were both held out of the Seattle game but are probable for Sunday's tilt, while safety Quinton Carter (knee surgery) is a possibility to go after returning to practice this past week.

Defensive end Jason Hunter (torn triceps), right guard Chris Kuper (broken forearm), defensive tackle Kevin Vickerson (concussion), safety Jim Leonhard (knee) and linebacker Keith Brooking (hamstring) are among the Denver players not likely to suit up on Sunday.

The 49ers could be entering their "dress rehearsal" game of the preseason with a thinner running back corps after free-agent pickup Brandon Jacobs and speedy rookie LaMichael James both left last week's test with injuries. Jacobs sprained his left knee on his only carry of the night, while second-round draft choice James was carted off with a left ankle sprain in the fourth quarter.

James was back at practice on Tuesday, however, and may be available to face a Denver squad that was gashed for 228 rushing yards by the Seahawks a week ago.

Standout pass rusher Aldon Smith (hip), fellow outside linebacker Ahmad Brooks (undisclosed) and cornerback Perrish Cox (undisclosed) appear on track to return for San Francisco after all three were inactive against the Texans. Tight end Delanie Walker is questionable for this week as he continues to recover from a knee injury, but was spotted on the practice field in recent days.

The Broncos hold an 18-15 advantage in their all-time preseason series with San Francisco and have prevailed in nine of the last 11 warm-up bouts between the clubs. The 49ers won the last such meeting, however, a 17-16 decision at Candlestick Park in 2009.

San Francisco also came out on top by a 24-16 count at home when the teams squared off during Week 8 of the 2010 regular season.