Fletcher will be used at nickel cornerback in place of the injured Johnathan Joseph.
Cincinnati will represent the 29-year-old Fletcher's fifth franchise in five years, but he remains a quality player particularly as a nickel defender.
Fletcher, who played in college at the University of Wisconsin, was a first-round choice of the Miami Dolphins in the 2001 draft. He is a veteran of 94 games, including 10 with Houston in 2007.
He has 157 tackles, seven interceptions and 31 passes defensed in stints with Miami (2001-03), San Diego (2004-05), Detroit (2006) and Houston (2007). Arguably, his finest season was with the Lions in 2006.
Details of the contract were not available.
Senior writer Len Pasquarelli covers the NFL for ESPN.com.