Reed, 26, has five career receptions for 66 yards over three years. All five catches came last year. To this point in his career, his biggest plays have come on special teams.
As a rookie in 2010, he led the NFL by averaging 29.3 yards per kickoff return. That included a 103-yard return for a touchdown to open the second half at Houston.
Jacoby Jones is returning kickoffs for the Ravens no, and Reed was buried on the depth chart at wide receiver. But the 6-foot, 195-pounder has a shot at making an impression with the Colts.
"This trade gives us a chance to improve in key areas moving forward," Indianapolis general manager Ryan Grigson said. "David is a very competitive football player and we welcome his style of play and energy. At the same time, we wish Delone well with his opportunity to play for another first-class organization and we thank him for his efforts."
Carter has started three games over two seasons with the Colts, running 133 times for 499 yards and five touchdowns. He was a fourth-round pick out of Syracuse in the 2011 draft. His best season came as a rookie, when he ran for 377 yards on 101 carries.