The Lions chose Prater over former Arizona Cardinals kicker Jay Feely after the two tried out for the team Tuesday, a league source told ESPN Insider Ed Werder.
Prater, Feely and former Tampa Bay kicker Connor Barth were all part of a kicker tryout in Allen Park, Michigan to replace Alex Henery, who was cut Monday after missing three field goals on Sunday during a 17-14 loss to Buffalo.
Prater, who made 25-of-26 field goals last season for the Broncos, was available after he was released by Denver last week after coming off a four-game suspension for violating the NFL's substance-abuse policy.
"We've got to find a performer," Lions coach Jim Caldwell said Monday. "That's basically what we have to get done. In that area you've got to get a guy who is consistent under pressure and will be able to get us some points on the board."
Caldwell was asked specifically about Prater on Monday, but declined to say then the team was going to work him out. Caldwell did say, though, they would look at the alcohol-related issues that led to his four-game suspension to start this season before they made a decision on a kicker.
"We'll look at each and every guy and make a determination based upon what we sense and feel about him on and off the field," Caldwell said. "That's how we do every guy. Suitable to the comfort level of all of us that are involved."
The Lions have been woeful kicking field goals all season as Henery and Nate Freese were a combined 4-of-12 over the first five weeks.
Detroit drafted Freese in the seventh round of May's draft and the rookie from Boston College beat out Giorgio Tavecchio during training camp. But he made only 3-of-7 field goals during the first three weeks of the season and the Lions waived him in favor of Henery, who went 1-of-5 over the past two weeks.
The Lions are 0-of-6 on field goals from 40-to-49 yards this season, an area where most teams are perfect at this point in the season. Prater made all eight of his field goal attempts from that distance last season and was also 6-of-7 from 50 yards or further.
Detroit is the third team since 2001 to start the season making only 33.3 percent of their field goals through five games, joining the 2009 Tampa Bay Buccaneers and the 2005 Chicago Bears.
Lions Sign Matt Prater
ESPN Lions reporter Michael Rothstein breaks down why the team decided to sign kicker Matt Prater.