The Colts placed Pierce (ankle) on the active/PUP list Monday, Stephen Holder of ESPN.com reports.
It's not an unexpected move after Pierce underwent ankle surgery in March. His recovery is expected to linger into training camp, and it's unclear if the wideout will be ready for the regular-season opener against the Ravens in 48 days. Without Pierce and with Michael Pittman now in Pittsburgh, the Colts look extremely thin at the position. Josh Downs, Ashton Dulin and Nick Westbrook-Ikhine is an unimposing top three.