The Indianapolis Colts travel east on Sunday to take on the Pittsburgh Steelers in a pivotal matchup between AFC postseason hopefuls.

At this point of the season, both teams enter with big question marks on the injury front. Here is how both teams' health is shaping up ahead of Sunday's matchup.

OUT — LB Jaylon Carlies (ribs), WR Ashton Dulin (hamstring), ED Arden Key (hamstring), TE Will Mallory (IR-knee)

QUESTIONABLE — WR Keenan Allen (groin), WR Darius Slayton (knee), CB Charvarius Ward Sr. (groin)

Slayton popped up on the injury report on Friday after suffering a knee injury in practice. This was potentially the week he was going to make his Colts debut, but now, that is in question.

With Carlies out, expect to see plenty of rookie Bryce Boettcher playing alongside Davis-Gaither.

Key suffered a hamstring injury in last Sunday's win over the Washington Commanders and is expected to miss multiple weeks. Jaylahn Tuimoloau is likely to start in his place, with rookies Caden Curry and George Gumbs Jr. likely to see more action. The Colts also signed veteran edge defender Carl Lawson to the practice squad this week.

Dulin missed Weeks 2 and 3 with an ankle injury and came out of Week 4 with a hamstring. Without him in the lineup, expect to see more of Laquon Treadwell on offense and Anthony Gould on kickoff returns.

Mallory's practice window opened up this week, and he practiced for the first time this season, but the Colts are not yet ready to activate him.

Allen and Ward both saw improvement in their participation throughout the week, so their "questionable" designation may be precautionary.

OUT — CB Jamel Dean (ankle), S DeShon Elliott (IR-knee), WR Michael Pittman Jr. (foot)

QUESTIONABLE — RB Rico Dowdle (toe), CB Jalen Ramsey (wrist)

Dean and Ramsey make up two-thirds of Pittsburgh's starting cornerback group, so their status is critical.

Former Colt Pittman, who was traded to the Steelers this offseason, has been dealing with a foot injury that kept him out of Week 2, and Steelers head coach Mike McCarthy said Thursday that Pittman had a setback and is expected to miss multiple weeks.

Since the season began, the Colts have missed matchups with former teammates Danny Pinter (knee), Braden Smith (foot), Nick Cross (illness), and now Pittman (foot).

The Colts and Steelers face off on Sunday at 1:00 p.m. ET on CBS in Pittsburgh at Acrisure Stadium.