The Colts will be without their top running back for at least another week. 

On Monday, Colts head coach Frank Reich announced that running back Marlon Mack will miss Sunday's game against the Titans. Mack sustained a hand injury during the Colts' Week 11 win over the Jaguars that required surgery. With Mack out, the Colts will continue to rely on Jonathan Williams, who rushed for 104 yards and a touchdown in last Thursday's loss to the Texans. On Sunday, the Colts' offense will face a Titans' defense that is 13th in the NFL in fewest rushing yards allowed and eighth in yards per carry allowed. 

Mack, a fourth-round pick in the 2017 draft, has rushed for 862 yards and four touchdowns this season while averaging 4.5 yards per carry. He's posted three 100-yard rushing performances this season that included a season-high 174 yards in the Colts' Week 1 loss to the Chargers

Despite the loss of Mack, the Colts still boast the league's third-best rushing attack behind the strength of an offensive line that includes center Ryan Kelly, tackle Anthony Castonzo and guards Mark GlowinskiQuenton Nelson and Braden Smith. The line has also helped quarterback Jacoby Brissett complete nearly 65 percent of his passes this season with 15 touchdowns and four interceptions. 

While they have had success on both sides of the ball, injuries to Mack, Brissett and receiver T.Y. Hilton have contributed to the Colts' recent slide, as Indianapolis is now 6-5 after a 5-2 start. The Colts' last three losses have been by a combined nine points that include a two-point loss in Pittsburgh, a four-point loss at home to the Dolphins and last Thursday night's three-point loss in Houston. 

Despite their recent skid, the Colts are just a game behind the Texans for first place in the AFC South division. Sunday's game against the Titans will be their second-to-last home game of the regular season, as the Colts will travel to Tampa Bay and New Orleans before hosting the Panthers in Week 16. Indianapolis will close out the regular season with a home game against the Jaguars.