With the start of free agency just 3 1/2 weeks away, the Saints have begun the process of getting under the expected 2013 salary cap of about $121 million.

ESPN.com reported Friday that linebacker Curtis Lofton, the team’s leading tackler last season, has restructured the contract he signed a year ago when he came over from the Atlanta Falcons.

By turning a $5 million roster bonus into a $5 million signing bonus, which can be pro-rated over the final five years of the six-year deal he received last spring, Lofton’s cap hit for 2013 will drop from from $7.1 million to $3.1 million.

That $4 million savings is just a start for the Saints, however, as they were reportedly more than $20 million over the expected 2013 salary cap recently.

According to NFL Players Association figures, Lofton — who was the Saints’ leading tackler in 2012 and is expected to be one of the inside linebackers in their new 3-4 scheme — will earn $1.1 million in base salary this season.

Lofton, a 6-foot, 241-pounder who will turn 27 in June, was credited with 157 total tackles and had one sack. He also forced two fumbles, recovered two fumbles and broke up 10 passes.