INDIANAPOLIS — After suffering, and playing through, a painful shoulder injury for the entirety of his rookie season, Marlon Mack missed the entire offseason workout program as he worked his way back from surgery.
Ready to go for the start of training camp, however, Mack looked like he hadn't missed a beat — despite the fact the Indianapolis Colts had installed a brand new offense under first-year head coach Frank Reich and offensive coordinator Nick Sirianni.
Perhaps the lead piece to the team's new "running back by committee" system, Mack earned the start in the Colts' first preseason game against the Seattle Seahawks, showing off his impressive burst from the very first play from scrimmage by taking a screen pass from quarterback Andrew Luck and sprinting down the sideline for a 17-yard gain.
Mack's 2018 preseason debut would last all of just nine snaps, however, as he suffered a hamstring injury with about three minutes to go in the first quarter of the Colts' eventual 19-17 victory at CenturyLink Field.
Mack has been sidelined in practices since that Aug. 9 preseason opener — as has veteran back Robert Turbin, who suffered an ankle injury in that same game — which has put the burden on the remaining Colts' backs to carry the load moving forward.
Because hamstring injuries can be so unpredictable, Reich initially labeled Mack's status as "week-to-week," but now we know there's a goal in mind for his return.
Reich recently told 1070 The Fan’s Dan Dakich that the team hopes to add Mack mack into the mix by its regular season opener Sept. 9 against the Cincinnati Bengals.
"It's hard to tell at this point," Reich said. "You shoot for Week 1, and hopefully we get him back Week 1."
Mack certainly showed flashes during his rookie season in 2017, when he became a change of pace to veteran starter Frank Gore, who utilizes more of a traditional "between the tackles" approach.
In 14 games, Mack had 93 rushing attempts for 358 yards (3.8 yards per carry) with three touchdowns, while adding 21 receptions for 225 yards and another score through the air.
His big-play potential was evident — he tied for 11th in the league with five rushes of 20 yards or more, despite having limited opportunities — but he also worked through some inconsistencies as a rookie, as one-third of his carries would go for no gain or negative yardage.
With Gore's tutelage as both a runner and a pass blocker — and with his shoulder feeling much better — Mack is hoping to take a big leap forward in his progression in Year 2. His position coach, Tom Rathman, told Colts.com's Caroline Cann at the start of camp that he was impressed with how quickly Mack had caught on to the system.
"He's picked it up well. He's learning the offense," Rathman said of Mack. "I thought he'd be a little bit behind on our drill work, but he stepped in and has done a nice job with it."
With Mack and Turbin sidelined — and considering the fact Turbin will sit out the first four weeks of the regular season due to a suspension — the team will lean on Christine Michael, Josh Ferguson, Nyheim Hines and Jordan Wilkins for the time being.
The Colts also have signed free agents Tion Green and Branden Oliver, who are getting opportunities to show what they can do in the final three preseason games.
"We hate to see bumps and bruises, and we hate to see little injuries that slow progression down, but when that happens it's always an opportunity for somebody else to step up," Colts offensive coordinator Nick Sirianni said. "Between Jordan (Wilkins) and Nyheim and all the backs, Christine Michael — they're all getting the opportunities to get some more reps."