Arth, who spent last season on the Colts practice squad, was in Green Bay on Monday for a tryout, according to ColtPower.com. The Packers have yet to officially announce the signing.
Arth, released by the Colts in the off-seasons of 2003 and '04, remained with the team as an assistant, breaking down game film for Peyton Manning. He was on the Colts' practice squad last season. The Colts usually only keep two quarterbacks on their active roster.
Arth, who played collegiately at Division III John Carroll University, will compete for a roster spot behind Brett Favre, if he decides to return, and Aaron Rodgers. Brian Wrobel, who signed as a free agent this off-season, is the only other quarterback currently on the Packers' roster. He is currently playing in NFL Europe.
Craig Nall, who served as Green Bay's third-string quarterback the last four years, signed a three-year deal with the Buffalo Bills on Monday.