Colts owner Jim Irsay first tweeted the news earlier Tuesday afternoon.
Moore, who turns 30 next month, played for the Steelers from 2008 through 2011. Last season, he rushed for 157 yards on 22 carries. His best season in Pittsburgh came in 2008 when he totaled 588 yards on the ground, including five touchdowns. He was primarily used as third-down back.
He began his career with the Minnesota Vikings in 2004 after being drafted by the team in the fourth round, 119th overall.
A report from Steelers Depot does point out that the deal is worth $825,000 over one year.