ENGLEWOOD, Colo. --Duke Ihenacho's improved play has been impossible to ignore — "if you're paying attention and you're not sleeping," as Defensive Coordinator Jack Del Rio said Friday. But that doesn't mean the depth chart is going to change overnight because of performance on the practice field, despite what the rotations may look like on a day-to-day basis in practice.

"He's done some good things. Thats good. But that's just a start. Nobody should get too far ahead of themselves," Del Rio said. "It's a long process. We haven't even begun to get into preseason games. There is a lot left to do."

Del Rio was talking about Ihenacho, but he — or any coach — could have been talking about numerous other players, who will have to prove the degree of their progress beginning with Thursday's preseason opener at San Francisco. One of them is Julius Thomas, whose workload has expanded exponentially this summer, but sits third on the depth chart behind Joel Dreessen and Jacob Tamme.

Ihenacho is listed on the second unit at strong safety behind incumbent Mike Adams. Ihenacho and Rahim Moore have worked together frequently on the first team during training camp, and were paired again with the No. 1 defense Saturday night. But for now, the Broncos will play wait-and-see before deciding whether to move Ihenacho up the ranks.

There were not many surprises on the first depth chart of the 2013 season, but there were a few items of note:

-- No rookies are on the first team. Five are on the second team on offense or defense: defensive tackle Sylvester Williams, right tackle Vinston Painter, running back Montee Ball and wide receivers Tavarres King and Quincy McDuffie. McDuffie is the only backup listed behind Welker, owing to the uniqueness of the slot receiver position, but it is more likely that another player — like Tamme, who saw some work in the slot last year — will actually fill that role.

-- Stewart Bradley is listed as the second-team middle linebacker behind Nate Irving, which generally reflects the repetitions to date in training camp. Steven Johnson, who had been mentioned as a potential starting candidate at that position, is listed on the third unit.

-- Lance Ball, who has been on the 53–man roster the last three seasons, sits seventh among running backs.

-- New arrival Ryan Lilja is the fourth-line center, behind Manny Ramirez, C.J. Davis and Steve Vallos, who signed with the Broncos on Monday in the immediate aftermath of Dan Koppen's season-ending torn anterior cruciate ligament.

-- Quentin Jammer is listed with the safeties; he's third at free safety behind Rahim Moore and David Bruton.

-- Injuries and practice rotation have shuffled the defensive tackles at times during practice, but the listed first-teamers are Terrance Knighton (at nose tackle) and Kevin Vickerson, as first projected in the offseason. Williams and Mitch Unrein are the second-teamers; Sealver Siliga and Romney Fuga comprise the third unit.

-- Shaun Phillips is the second-teamer at both right defensive end and strong-side linebacker. Lerentee McCray remains the third-team strong-side linebacker, but his progress bears monitoring after a recent burst of big plays.