ENGLEWOOD, Colo. -- **From a distance, you couldn't tell of anything unusually amiss when Broncos medical personnel examined Rahim Moore's left leg on a table behind the team bench area during the second quarter Sunday night.
But a few minutes later, Moore walked up the tunnel behind the Broncos sideline -- which is usually the sign that the injury is something more than a momentary concern.
"He was just suddenly gone," said cornerback Chris Harris, Jr.
In the hours that followed Moore's departure, his affliction was worse than could have been envisioned: compartment syndrome, an affliction that threatens limb and life if not properly -- and immediately -- treated.
Moore went to the sideline right after Jamaal Charles' 35-yard sprint to the left side. A handful of tweets immediately after the play criticized the angle that Moore took on the play. That's one of the downsides of the immediate-reaction culture of today; no one watching could possibly have known what Moore was enduring at that moment.
"I knew there had to be something wrong with him when Charles busted through on that long run and he didn't have the acceleration to go make the tackle," said Harris. "Usually he would make the tackle and it would be over. But for Jamaal Charles to get the corner like that, I knew something was wrong with him."
What did reveal itself in that moment was an unusual lack of speed from the typically swift safety; he got turned so fast and was so quickly out of the play that something had to be wrong; it was completely unlike his play against the run this season. It is possible the circumstances of the moment might have been a blessing, as quick diagnosis is crucial to treatment of compartment syndrome.
Moore's prognosis is drastically improved by the immediate identification of the problem; according to the National Institute of Health, "the outlook is excellent for recovery of the muscles and nerves inside the compartment" with "prompt diagnosis and treatment." Had the condition been undiagnosed and allowed to persist, Moore would have been at risk of permanent damage to muscles and nerves -- and perhaps worse.
But as Moore struggled, the Broncos had to go on. Mike Adams was immediately inserted into the lineup, and the defense kept going. By the end of the drive, the defense was without Moore and linebacker Danny Trevathan, who was being treated on the sideline, but still turned in a goal-line stop, thanks to Trevathan's replacement, Steven Johnson.
"Being able to have a guy like Mike that can step in (whether) Duke is out or Rahim is out, is big," Harris said.
The argument can be made that no area of the Broncos roster has better depth than the secondary. Champ Bailey's injury has hurt the Broncos, but it hasn't cost them dearly, since Harris, the slot cornerback, is better than many first-teamers in the league and can play every down. Also, rookie Kayvon Webster has emerged as a tough, smart and aware presence as the third cornerback playing outside when Harris shifts inside in nickel and dime packages. Adams, an experienced starter who played alongside Moore last year, offers enough experience to ensure that Duke Ihenacho can continue his aggressive play.
There are limits to the depth. Denver has one more experienced backup safety in special-teams captain David Bruton, who started in the 2011 playoff run. But beyond that, the only option is second-year player Omar Bolden, who was converted from cornerback earlier this year. But Bolden has seen some work on defense, as has veteran Quentin Jammer.
"I've never been on a team where everybody (in the secondary) plays. It's a really unique thing," said Harris.
And Moore's injury is just another blow for a Broncos starting lineup that has been more battered than it was in 2012.
Last year, Broncos starters lost 34 man-games. This year's total will be at least 32, since left tackle Ryan Clady will not return until 2014 because of a Lisfranc injury, and is certain to exceed that. To what degree depends on Moore's timetable and the natural attrition of players going forward in a high-speed, collision sport.