Conner, 25, played his first four seasons with the Steelers. The 2018 Pro Bowl selection became a free agent in March. He had toe surgery this off-season, but is expected to recover in time for the start of the 2021 season.
Conner is expected to split carries with fellow running back Chase Edmonds in the Cardinals backfield. Former Cardinals starting running back Kenyan Drake left the team in free agency and signed with the Las Vegas Raiders last month.
Conner entered the league as a third-round pick in the 2017 NFL Draft. The University of Pittsburgh product picked up a career-high 1,470 yards from scrimmage and 13 touchdowns in 13 games in 2018, but missed nine games over the last two seasons due to injuries.
The Steelers have Benny Snell Jr., Anthony McFarland Jr., Kalen Ballage and Jaylen Samuels at running back on their depth chart.
The Steelers finished last in rushing, with 1,351 yards last season. The Cardinals had the seventh-best rushing offense, with 2,237 yards in 2020.