Bill Belichick isn't done configuring his roster in preparation for next Sunday's opener against the Tennessee Titans.

The New England Patriots claimed former Saints center Matt Tennant off waivers to get New England's roster to 53, then swapped a late 2015 draft pick to the St. Louis for wide receiver Greg Salas, and capped off the day with the surprising release of veteran linebacker Bobby Carpenter.

Carpenter, a former first-round pick of the Dallas Cowboys, signed a one-year deal with the Patriots and figured to be a top reserve at outside linebacker. 

His release leaves the Patriots with just five linebackers -- Jerod Mayo, Brandon Spikes, Dont'a Hightower, Tracy White and Mike Rivera at linebacker -- after finishing last season with seven linebackers. 

In an emergency, defensive end Rob Ninkovich, who served as a linebacker last year, could slide back to his old spot and it's worth nothing that rookie safeties Tavon Wilson and Nate Ebner lined up there in sub packages throughout the preseason.

Salas became a favorite of Patriots offensive coordinator Josh McDaniels last season when he was coaching in St. Louis. The 2011 fourth-round pick caught 27 passes for 264 yards before suffering a broken fibula Week 9 against Arizona.

His arrival gives New England five wide receivers after Jabar Gaffney, Donte Stallworth and Deion Branch were released earlier this week.

Salas reportedly fell out of favor with the new coaching staff in St. Louis during training camp, but showed potential by catching 225 passes for 3,479 during his last two seasons at Hawaii.

He will likely compete with Julian Edelman and Matthew Slater for the third wide receiver spot. 

Tennant, 25, a product of Boston College, was a fifth-round choice of the Saints in 2010. He appeared in 28 games over the last two seasons. The 6-foot-5, 300-pounder also possesses the ability to play guard and arrives one day after New England cut longtime center Dan Koppen.

Patriots announce practice squad: OL Thomas Austin (2nd year, Clemson), FB Eric Kettani (2nd year, Navy), WR Sam Kirkland (rookie, Kent State), OL Matt Kopa (2nd year, Stanford), TE Alex Silvestro (2nd year, Rutgers), LB Jeff Tarpinian (2nd year, Iowa) and DB Malcolm Williams (2nd year, Texas Christian).

New England has one spot open on the practice squad.

Nick Underhill covers the Patriots for MassLive.com. Follow him on Twitter @CBSSportsNFLNE or @nick_underhill.