INDIANAPOLIS — Marlon Mack's availability for Sunday's rematch against the Jacksonville Jaguars is still up in the air, but the Indianapolis Colts running back took a positive step forward on Thursday.
Mack, who is in the league's concussion protocol after being knocked out of last Sunday's Week 12 victory over the Miami Dolphins, made his return to the practice field, which is one of the key boxes required to be checked before he can be cleared for game action.
Mack was even listed as a full participant on Thursday's practice report.
Colts head coach Frank Reich did not speak to the media on Thursday, but is expected to address reporters on Friday after practice, when he typically announces who is out, doubtful and questionable for the upcoming game.
Mack was one of a few key playmakers who made their return to the practice field Thursday after missing Wednesday's first practice of the week to prepare for the Jaguars. Others who returned today included wide receiver T.Y. Hilton (groin), tight end Eric Ebron (back) and safety Clayton Geathers (knee).
Starting linebackers Darius Leonard (shoulder/knee) and Anthony Walker (shoulder), meanwhile, emerged for practice after practice had already started and were seen working with a team trainer off to the side once a special teams period began early on in the portion of practice available to be seen by the media. Leonard was later listed as a limited participant, while Walker was listed as a full participant.
Those who were not seen at practice early included safety Mike Mitchell (calf), center Ryan Kelly (knee) and tight ends Mo Alie-Cox (calf) and Erik Swoope (knee). Both Mitchell and Swoope practiced on Wednesday.
Mack exited last Sunday's game against the Dolphins in the fourth quarter to be evaluated for a concussion, and didn't return. Head coach Frank Reich confirmed Monday that Mack was in the league's concussion protocol.
Mack, who missed four of the Colts' first five games of the season with a hamstring injury, has been a steady presence in the Indy backfield in his second NFL season, running the ball 109 times for 556 yards (5.1 yards per carry) and four touchdowns on the ground, while adding 11 receptions for 74 yards and another score through the air.
With Mack on the sidelines late in last Sunday's game, rookie Nyheim Hines got a majority of the team's carries down the stretch. The team also has another rookie, Jordan Wilkins, as well as third-year pro Jonathan Williams available at the running back position on its active roster.
» DNP: TE Mo Alie-Cox (calf); C Ryan Kelly (knee); S Mike Mitchell (calf); TE Erik Swoope (knee)
» Limited: TE Ryan Hewitt (ankle); WR T.Y. Hilton (groin), S Malik Hooker (hip); LB Darius Leonard (shoulder/knee)
» Full: TE Eric Ebron (back); S Clayton Geathers (knee); RB Marlon Mack (concussion); LB Anthony Walker (shoulder)