A $500,000 a year increase in an offer by the Denver Broncos could lead to a five-year contract for left tackle Ryan Clady, a source said.

Since last year, the Broncos have been offering Clady a five-year, $50 million contract. By increasing the offer to $52.5 million and showing a willingness to guarantee significantly more than 50 percent of the contract, the Broncos have Clady thinking about accepting the offer.

Clady is an unsigned franchise player. The deadline is Monday for franchise players to accept long-term deals. After Monday, the franchise player and the team can only sign one-year contracts for the rest of the season.

As of now, the non-exclusive franchise tag will ensure a $9.828 million salary for Clady in 2013.

Clady, 26, played through a right shoulder injury in 2012 that required offseason surgery but was still effective as Peyton Manning's blindside protector, allowing just one sack.