Bears coach Matt Nagy said Peters signed with Chicago to compete for the starting left tackle job. The Bears' original choice to play left tackle, rookie second-round pick Teven Jenkins, has been sidelined since the beginning of training camp with a back injury.
"It's about familiarity with a guy that's played in this league for a long time and has been very good," Nagy said Saturday. "We understand that he's older. There is a history with [Bears offensive line coach] Juan [Castillo]. Juan worked with him several years ago in Philadelphia. I was also there in Philadelphia.
"For us to bring him in, he knows there is a great competition. We are trying to do everything we can to provide protection and have a great run game. I think he's coming in here to compete to be the starting left tackle. It's open, man. It's a competition."
The 39-year-old Peters played the past 12 seasons of his stellar career with the Philadelphia Eagles, with whom he earned seven of his nine Pro Bowl bids.
He came back to the Eagles on a one-year deal last season to play guard then moved back to left tackle with a sweetened contract when Andre Dillard suffered a torn biceps injury in August.
Peters played eight games in 2020 and was placed on injured reserve in December with a toe injury that required surgery. He has dealt with multiple injuries over recent years and has played 44 of a possible 64 games since 2017.
An undrafted free-agent pickup by the Buffalo Bills in 2004, Peters has put together a résumé worthy of Hall of Fame consideration during his 17 NFL seasons, with two first-team All-Pro selections.
ESPN's Jeff Dickerson and Tim McManus contributed to this report.