The Commanders signed offensive tackle Aaron Monteiro on Monday, the team announced.
Monteiro became a free agent May 12 after the Panthers waived him.
Monteiro played four seasons at Boston College, starting 32 consecutive games. He earned third-team All-ACC as a senior and signed with the Dolphins as an undrafted free agent in 2019.
Miami waived Monteiro, who signed with the Patriots later that season. New England cut him six days later.
Monteiro then signed with the Panthers, and he spent three seasons on the practice squad.
Monteiro, 25, has never seen action in the regular season.