INDIANAPOLIS -- Colts receiver Austin Collie could return to the football field later this week after being diagnosed with yet another concussion.
Collie told team officials that he "felt good" when he returned to the team complex Monday, but coach Chuck Pagano told reporters later Monday that the four-year veteran would not play again until passing a series of tests.
The fourth-year player was injured in the first quarter of Sunday night's 26-24 loss at Pittsburgh after taking a blow to the head from Steelers linebacker Larry Foote.
It's the third time since November 2010 that Collie has left a game because he had a concussion.
"Again, player safety is first and foremost. We are always going to err on the side of caution as we talked about before. I'm more interested in the health of these guys than just throwing them back out there," Pagano said.
Some doctors contend the severity of concussions is more important than the number or the frequency of them.
But the NFL has taken a stronger stance on head and neck injuries recently in hopes of protecting players. The league has imposed tougher, more consistent protocols to dealing with suspected concussions and how soon those players can return to the field.
This year's tweaks included the addition of certified athletic trainers in booths to keep an eye out for possible head injuries, and adding video feeds on sidelines.
Pagano said the team did use game video to help them make the diagnosis on Collie.
"They take him through a battery of tests now once you determine (the concussion), they look at what happened on the tape," Pagano said. "They got the guy up in the box, the doctor, and he'll say he did a take a shot, blow to the head, so to speak. They come in and evaluate him and once they do determine he had a concussion, he'll go through a battery of tests throughout the week. Like I said, it'll be day to day and you just see how they progress."
Collie missed six of the last eight regular-season games and most of a seventh in 2010 after taking two big hits.
The first came in November when he was hit with a high-low combination by two safeties at Philadelphia. The blow left him unconscious and he was taken off the field on a stretcher. Six weeks later, he sustained another concussion against Jacksonville and missed the rest of the season.
Colts players took Monday off and were not available to comment, but Collie used his Twitter account to respond.
"Thanks to everyone for their thoughts and prayers. I'm doing really well and feeling great," he wrote.
Collie was one of three key Indy players injured Sunday night.
The Colts got good news on linebacker Robert Mathis, who left in the first quarter with a strained shoulder. Pagano said Mathis, who played his first nine years at defensive end, was "fine."
That's good news for a young group of linebackers that had already lost veterans A.J. Edds and Scott Lutrus with season-ending anterior cruciate ligament injuries and starting inside linebacker Pat Angerer for at least six weeks with a fractured foot.
The other big name to go down was defensive end Cory Redding. He left on the game's first series with a strained left knee.
Pagano said an MRI showed Redding had a mild sprain of the medial collateral ligament and was likely to miss one week or perhaps a little longer. Redding has already missed one week of training camp with an undisclosed left elbow injury.
Redding is a key cog in the Colts' revamped defense because he played in the same system in Baltimore for the past two seasons. Indy signed Redding for three primary reasons: His familiarity with the defense, his ability to teach the defense to teammates and his 6-foot-4, 315-pound body made the Colts significantly larger across the defensive line.
Pagano was relieved with the news.
"Well, you just say your prayers, keep your fingers crossed. It's always hard to see two guys like that or anybody for that matter go down early," he said, referring to Redding and Collie. "Obviously, we feel fortunate that things came out the way they did."
The injuries were the biggest concerns to come out of a game in which Andrew Luck looked remarkably poised again and the defense again proved stout around the goal line.
Luck threw two interceptions, but led the Colts on touchdown drives after both turnovers.
The defense has now given up just one touchdown in eight quarters, though Pittsburgh did return Luck's first interception for a score.
And Pittsburgh still needed a partially-blocked 22-yard field goal to trickle over the crossbar in the final minute to beat Indy.
Pagano has had few complaints about his team's performance, so far, other than, of course, staying healthy.
"He (Collie) came in and felt really good today, which was positive for us," Pagano said. "We'll just take it day-to-day with him, but we'll be smart."