McKelvin was set to make a base salary of $2 million with a roster bonus of $1.2 million in 2017. By cutting him, the Eagles gain $3.2 million in cap space.
The Eagles started the process of trying to free up resources by asking veteran left tackle Jason Peters to take a pay cut. They are expected to continue to free up money over the next four weeks before the start of free agency on March 9.
McKelvin, who played under defensive coordinator Jim Schwartz in Buffalo, signed a two-year, $6.2 million deal last offseason. He established himself as the team's top corner during the spring and summer but injured his hamstring early in the season and never fully rounded into form.
He appeared in 13 games and finished with two interceptions and 16 passes defensed.
Fellow starter Nolan Carroll is set to become a free agent, so it's possible the Eagles will have two new outside corners in 2017.
An upgrade is needed. Cornerback play was an issue for most of the season. The Eagles' defense yielded 57 pass plays of 20-plus yards (sixth-highest in NFL), and were the most giving team in the league on deep balls down both the left and right sides of the field.
Executive vice president of football operations Howie Roseman pointed to the corner position in particular when emphasizing that the team needs to get away from the "band-aid" approach. They have largely gone the free-agent route for a number of years to fill the cornerback posts, with minimal success. That's been largely out of necessity given that they haven't drafted a corner in the first round since selecting Lito Sheppard 26th overall in 2002. They invested a second rounder in Eric Rowe in 2015, but traded him to the eventual-champion New England Patriots this past September after just one season.
With a quality crop of cornerbacks in this draft, the Eagles are expected to replenish the position come April, and perhaps before via free agency.