Barth, 28, hasn't kicked in a regular-season game since 2012, as he missed the 2013 season after sustaining a torn Achillies tendon in a charity basketball game.
With the Tampa Buccaneers in 2012, Barth went 28-of-33 with a long of 57 yards. For his career—he spent 2009-12 with the Bucs after breaking into the league with the Kansas City Cheifs in 2008—Barth is 101-of-121 on field goal attempts.
Barth was cut by the Bucs in the preseason after the team elected to go with first-year kicker Patrick Murray.
McManus, 23, was 9-of-13 this season, his first in the league. In the last four games in which he attempted a kick, McManus missed one each in three of those contests. His 69 percent success rate on field goals rates 32nd in the league.
McManus was traded to the Broncos before the season from the New York Giants after long-time Broncos kicker Matt Prater was suspended four games for violating the NFL's substance abuse policy and ultimately released by the team.
McManus also spent time with the Indianapolis Colts in 2013 after going undrafted out of Temple.
- Mike Fiammetta