Head coach Shane Steichen noted Friday that Pierce (concussion) won't play Sunday against the Titans, Amanda Foster of the Colts' official site reports.
Pierce, who sustained a concussion during Week 15 action, didn't practice Wednesday or Thursday but participated in Friday's session, wearing a non-contact jersey, per Nate Atkins of The Indianapolis Star. However, with the wideout having been ruled out and targeting a potential return to action Sunday, Dec. 29 at the Giants, Adonai Mitchell figures to see added opportunities this weekend alongside fellow WRs Michael Pittman and Josh Downs.