And then there's safety for the Broncos.

A decidedly not so safe place, where there has been a growing line to play at what cornerback Champ Bailey called "your last line of defense."

In the Broncos' win against the the Jets, Vernon Fox, a level- headed sort who is in his seventh NFL season and understands the ebb and flow of Football life, became the fourth player in the past five games to start at free safety. He followed Roderick Rogers, who had started the season on the practice squad, made his first career start against the Raiders and was released the next week.

After Fox was credited with three tackles in Sunday's 34-17 victory and returned a fumble 23 yards for the Broncos' first touchdown, coach Mike Shanahan said he expects Fox to get the start Sunday against the Kansas City Chiefs (2:05 p.m., CBS 4).

"You try not to approach it that way - about who's in, who's out," Fox said. "You never want to play a game nervous, second-guessing yourself or worrying about the repercussions of your play. You just play one play at a time.

"But I'd be dishonest if I didn't say it's in the back of your mind, that one bad performance could put you back on the sideline. So you just put your best effort in and let that take care of itself."

Fox's teammates already have lauded his professionalism - he has been with the team only since late September - and his even-keel demeanor. A quality special-teams player, Fox never has started more than six games in a season.

But things have been bubbling at safety for the Broncos since training camp, and Shanahan continues to search for what he called "a difference maker" at the position.

First, there was the question of John Lynch's future before his August release.

Then Marlon McCree, a free- agent signee who started Denver's first six games at free safety, was benched for a game in favor of Calvin Lowry.

After making that start, Lowry was benched in favor of McCree. But McCree injured his left ankle late in the loss to the Dolphins, so Lowry was in for two more starts before giving way to Rogers.

Then Rogers was released, so Fox started against the Jets.

"It's a hard position," Bailey said. "I think physical ability is more of an issue at corner than at safety, but when you talk about safety, you've got to have the attitude to tackle, cover - there's a lot of things you've got to be very good at to play safety. And mentally, you've got to be probably the sharpest guy on the field.

"And you're the last guy out there, so if anything breaks and then you mess up, everybody's going to see it and it's going to show up on tape."

Fox has played strong safety and free safety - free safeties often play deeper, more in the open field, away from the line of scrimmage - at different points in his career and is a quick study.

He has played two seasons with the Chargers, two with the Lions and the past two with the Redskins. He's hoping to stay in Denver for a while.

"Early in my career, I carried a lot of bitterness about how things went," Fox said. "And I can say every time I've been released, there's kind of been some uncertainty, or it's not been very clear what I could have done to enhance my chances of staying on the roster. But now, I kind of take it with a grain of salt. This is a business, and I don't take it personally any longer.

"You are a human being, you do have emotions, you have feelings, things bother you. But someone told me once the NFL is like Baskin-Robbins: If one flavor doesn't work out, there's 31 other flavors to try. So you just approach it as such. You hope there is another team that appreciates your talents."

ETC.: The Broncos formally moved defensive tackle Josh Shaw to injured reserve Tuesday. Shaw suffered a dislocated elbow and some ligament damage in the Broncos' win against the Jets on Sunday. . . . The Broncos reported no formal workouts to the league. . . . Shanahan, quarterback Jay Cutler and running back Peyton Hillis were each nominated for the league's weekly awards - coach, player and rookie of the week. Fans can vote at NFL.com.

INFOBOX

Safety dance

The Broncos have used four players at free safety in the past five games. The latest, Vernon Fox, offers a quick breakdown of the duties at free safety and strong safety:

* Free safety

"Needs to have a bit of range, cover sideline to sideline, read the quarterback, and one of the biggest things I'm adjusting to is really being in open space. Being able to come downhill and make tackles in space."

* Strong safety

"You're down closer to the ball, you're forcing the run. It seems like you're a lot closer to a lot of the action at times. But for the most part, they're somewhat interchangeable, but there's definitely a different skill required for both."