Colts blog Stampede Blue acknowledges that a second-round pick was a steep price to pay but Indy clearly needed help at the cornerback position. Davis should immediately provide a more talented option.
Giving up a second rounder is a steep price, especially for a Colts team with so many holes. However, it was obvious that the front office was not happy with the corner play in preseason. The starter for the first preseason game (Justin King) wasn't even active for the third game for reasons that still have not been explained. Kevin Thomas, the "starter" all throughout OTAs, was traded to Philadelphia (and later released by them) three days into training camp.
Davis has had a tough training camp with the Dolphins after reportedly showing up out of shape. He had clearly fallen out of favor with the Dolphins coaching staff and a fresh start was probably the best thing for all parties.