ENGLEWOOD, Colo. --In August, cornerback Tracy Porter had what was diagnosed by the team's medical staff as a seizure.
At that time, he was held out of practice leading up to the team's second preseason game against the Seattle Seahawks, and missed the game before he was cleared by the medical staff to resume participation.
Porter did not experience any related symptoms until shortly before the team was set to fly to San Diego to take on the Chargers in Week 6.
He was held back in Denver and listed as out of the game with an illness by the team's medical staff for precautionary measures, after he experienced symptoms similar to those he felt in August related to the seizure.
After the bye week, Porter was back at practice on Wednesday on a limited, non-contact basis, but did not participate on Thursday.
Head Coach John Fox addressed the situation after Thursday's practice session.
"Right now, he's being evaluated," said Fox, who described Porter as "day-to-day." "When we figure out how to deal with the illness, then he'll be out here."
"When he's cleared to be physically able to practice, he'll be out there," he continued.
Fellow cornerback Champ Bailey said he and his teammates are thinking about Porter as he deals with the illness.
"It's a question mark -- you don't really know what's going on," Bailey said. "I try to help all the young players here but in this situation there's not much I can do. We're all praying for him and hopefully he'll be back sooner than later."
On Thursday afternoon, Porter took to Twitter to thank fans for their concern and support.
"I would like to thank EVERYONE for the prayers and wishes," Porter tweeted. "It really means a lot to me."
Prior to Week 6, Porter had played in all five of the team's games, contributing 21 tackles, one interception -- which he returned 43 yards for a touchdown -- two tackles for loss and six passes defensed. He took home AFC Defensive Player of the Week after his performance in Week 1.
Against the Chargers, young cornerbacks Chris Harris and Tony Carter stepped up in Porter's absence, chipping in two turnovers -- and one defensive touchdown -- apiece.
Defensive Coordinator Jack Del Rio said he would defer to team doctors in regards to Porter's status for Sunday, but if the cornerback can't play against his former team, he has confidence in the rest of the secondary.
"Our group, we expect the next guy up to play," Del Rio said. "They stepped up the last time out and played well in some big moments and we just expect them to go out and do their job and be part of the team. As a team, we have to find a way to be better than this team and they have to do their part to help us."
