Phil Costa, a center who signed with the Colts as a free agent last month, has surprisingly decided to retire.

The Colts announced today that the 26-year-old Costa, who previously spent four years with the Cowboys, is calling it a career.

“Phil feels it’s in his best interest to retire from the game,” Colts General Manager Ryan Grigson said in a statement. “We certainly understand and wish him nothing but the best.”

The Colts may understand, but it’s a difficult decision to understand from the outside: There had been no indications that Costa was having any physical problems that would prevent him from playing many more years in the NFL.