Indianapolis Colts linebacker Robert Mathis is one step closer to getting back in the lineup.

Tuesday, the team activated Mathis from the physically unable to perform list, clearing the way for the 34-year old to return to practice.

Mathis missed all of last season after sitting out the first four games while serving a suspension for violating the league's policy against performance-enhancing drugs and then tearing his Achilles training for his return.

The 13-year veteran, who led the NFL in sacks with 19.5 in 2013, has said he's targeting the team's season-opener against the Buffalo Bills to make his return, but team owner Jim Irsay cautioned that Mathis may not be ready to play until late September or early October.

(h/t ESPN)