Simms has high-ankle sprain

Denver Broncos backup quarterback Chris Simms suffered a high-ankle sprain, and according to a team source, he could be out of action anywhere from two to four weeks.

To bolster their depth at the position, the Broncos signed free agent Ingle Martin later Wednesday.

Denver has two preseason games remaining -- Sunday night against the Bears and Sept. 3 against the Cardinals -- and were down to two quarterbacks in starter Kyle Orton and rookie sixth-round pick Tom Brandstater.

Typically, teams like to rest many of their starters in the last preseason game, meaning Brandstater could be showcased against the Cardinals.

"Under our current situation, with only two quarterbacks that can come out and practice, it felt like it was better for us to [add Martin]," coach Josh McDaniels said. "He's got good size, a decent arm. He's a smart kid. He's a guy that we felt like could come in and help us compete right now and see what happens."

Martin joined the Broncos in time to take part in Wednesday's practice, though he went through the workout in a numberless orange quarterback's jersey.

"Hopefully, the equipment guys will hook me up tomorrow," Martin said with a smile.

The Broncos are the fourth NFL team for Martin, who was released earlier this month by the Kansas City Chiefs after splitting time last season between their active roster and practice squad. Martin came into the league in 2006 as a fifth-round draft choice of the Green Bay Packers. He also spent two years with the Tennessee Titans.

"When you're a guy like me, you just want an opportunity and that's what I've got here," Martin said. "Hopefully, I can come in and show them a little bit of what I can do and make myself stick."

Martin said he's taking a crash course on the Broncos' offensive scheme in hopes of being able to function in the system as quickly as possible. It was uncertain whether he would see any playing time in Sunday night's exhibition against Chicago.

Simms suffered the injury when Seahawks pass rusher Nick Reed fell on his left ankle during the third quarter of Saturday's 27-13 loss at Seattle.

Simms' injury is the latest setback for the injury-plagued player. Since rupturing his spleen nearly three years ago, Simms has taken only six regular-season snaps, all of them coming last season for the Titans.

Adam Schefter is an ESPN NFL Insider. The Associated Press contributed to this report.