Joel Dreessen likely out until Week 1

Joel Dreessen, who has been the Denver Broncos' starting tight end throughout the early portion of training camp, is expected to miss the remainder of the preseason because of arthroscopic surgery on his left knee.

The Broncos formally break training camp just before their Aug. 17 preseason game in Seattle, but Dreessen is now expected to be held out of all four preseason games. This will be the second surgery Dreessen has had on the knee in just more than two months.

"Different spot, same knee,'' Coach John Fox said Monday. "We performed the scope this afternoon ... but we'll keep you posted.''

The news of Dreessen needing surgery had been reported earlier by USA Today Sports.

Dreessen, who finished with 41 catches last season, had arthroscopic surgery on the same knee in late May and was held out of the Broncos' offseason workouts in June, including the team's mandatory three-day minicamp.

Dreessen had participated through the first week of training camp, but was held out of Saturday night's scrimmage after experiencing pain and some swelling in the knee. Dreessen had been the most consistent blocker/receiver combination at the position and often played as the single tight end in the three-wide receiver formation as well as the on-the-line option in the two-tight end look.

He led all of the team's tight ends last season with 863 snaps, or 75.5 percent of the team's offensive plays.

With Jacob Tamme also having missed time of late with a thigh injury, Julius Thomas will be pushed into a bigger role for the remainder of the preseason. Thomas has one career catch -- as a rookie against Cincinnati in 2011 -- before an ankle injury derailed both his '11 and '12 seasons.

Thomas, a fourth-round pick in the 2011 draft after playing just one year of football at Portland State following a four-year basketball career at the school, is healthy and has steadily worked his way into more and more work with the starters in this training camp.

"I like what Julius has done,'' quarterback Peyton Manning said. " ... He's worked really hard to get back and you can see what he can bring to the offense.''

Meanwhile, right tackle Orlando Franklin left Monday's practice with a right hip injury. After Franklin departed, right guard Louis Vasquez moved out to right tackle and newly-signed Ryan Lilja went in at Vasquez's right guard spot.

Jeff Legwold covers the Broncos for ESPN.com.