Cundiff missed Friday's practice with a knee injury, just days after he staved off competitors to keep his job.
Cundiff hurt the Browns in Sunday's 25-24 loss to the Colts with a first-half missed attempt from 40 yards out. He made 22 of 29 kicks this season, but Cundiff's limited range had hindered the Browns' offensive strategy as well.
Hartley appeared in 57 games with the New Orleans Saints from 2008-2013 and converted 82 of 101 field goal attempts. However, going from a cushy indoor home stadium to the wintry Cleveland weather could be an adjustment for a late-season addition.
The latest Around The NFL Podcast previews the Week 15 schedule and recaps the Cardinals' win over the Rams. Find more Around The NFL content on NFL NOW.