New England Patriots cornerback Darrelle Revis has been the catalyst for a pass defense allowing just 235 yards through the air per game. But his contract gets a little tricky after this year, posing problems for the Patriots.

For salary-cap purposes and to shield Revis from a franchise tag, New England gave the three-time All-Pro a second year worth $20 million in 2015. That year counts $25 million against the cap, an astronomical figure. The Pats are unlikely to pay such a sum which means Revis will either become an unrestricted free agent after the season or sign a long-term extension. Both parties are hoping for the latter.

"Ask Bill [Belichick]," Revis said when asked about potentially hitting the open market this summer, according to ProFootballRumors. Patriots owner Robert Kraft seems inclined to not let that happen.

"He likes what he sees here," said Kraft. "And I know we like having him here. We'll just have to see if we can do some long-term business. That's what we really want to do. Let's get through the season and see what happens."

Pro Football Focus rates Revis as the Patriots' top cornerback with a +6.6 grade this season. However, should the 29-year-old move on from New England after the season, it would be his fourth team in as many years. Revis was traded from the New York Jets to the Tampa Bay Buccaneers in 2012 after tearing his ACL. He played just one season with the Bucs before being released for cap salary cap relief. The Patriots signed him in free agency.

Several teams are in the market for a cornerback should Revis and the Patriots not agree to a long-term deal. The Baltimore Ravens, Chicago Bears, Detroit Lions and Philadelphia Eagles all could use upgrades in their secondary. Revis, even approaching 30 years old, would immediately help in that area.