Indianapolis Colts leading rusher Marlon Mack suffered a left hand fracture in Sunday’s home 33-13 home win over the Jacksonville Jaguars that will likely sideline the running back indefinitely, according to league sources.

Mack, who rushed for 109 yards on 14 carries before exiting in the third quarter, will meet with specialists to determine the severity of the injury and if surgery is needed.

That means the Colts (6-4), who already have their share of key players injured, will be short-handed again for a Thursday night showdown at the Houston Texans (6-4) to determine who takes over first place in the AFC South Division.

The Colts turned to Jonathan Williams and Nyheim Hines to handle the carries after Mack’s early exit and the team finished with 264 rushing yards, the most for the franchise since 2006. Williams, a fourth-year pro with just 95 career rushing yards before Sunday, had a career-best 116 against the Jaguars. It’s just the fourth time in Colts history to have two 100-yard rushers in one game, and it hasn't happened since 1985.

Hines added a TD run against the Jaguars.

Mack is enjoying the best season of his three-year NFL career with 862 yards rushing on 192 attempts with three TDs. He had 908 yards rushing in 12 games last season.

Mack provided a highlight-reel run in the second quarter as he spun outside twice to avoid tacklers on a 13-yard TD rush to tie the game.

The Colts are already without four-time Pro Bowl wide receiver T.Y. Hilton — Sunday’s win was the first without him in eight games since 2012 — as well as wide receivers Devin Funchess and rookie Parris Campbell as well as cornerback Pierre Desir. Campbell, a second-round pick, suffered a hand fracture two games ago that required surgery and is expected to sideline the rookie for a month.

Reserve running back Jordan Wilkins, second on the team with 165 yards rushing on 27 carries, was also sidelined for Sunday with an ankle injury.

Williams had only 1 yard rushing on two carries this season before Sunday’s career effort.

Hines, a second-year pro typically used as a pass catcher, has 77 yards rushing on 25 carries with one TD. He’s also the team’s second-leading receiver with 30 catches for 242 yards.