INDIANAPOLIS -- Colts wide receiver Alec Pierce, the team's leader in receiving yards, will miss Sunday's game against the Tennessee Titans with a concussion, coach Shane Steichen said Friday.

Pierce hit his head on the turf on a fall in the end zone during last Sunday's loss to the Denver Broncos.

His absence leaves a void at receiver for Indianapolis given his role as a consistent deep threat. Pierce leads the team with 645 receiving yards, with league-high 22.2 yards per reception and a team-leading five touchdown catches.

The absence of Pierce will mean a more expanded role for rookie Adonai Mitchell, who has had a rocky first season, including last week's failed trick play that resulted in a fumble-return touchdown for Denver. Backup Ashton Dulin, who is coming off an ankle injury, also hopes to return.

Meanwhile, starting weakside linebacker E.J. Speed will also miss the game with a knee injury. He is likely to be replaced by veteran Grant Stuard.