Freeney is in San Diego with the Chargers now, cut loose by the Colts in an all-business, no-sentiment move forward.
“It's weird; it's really weird,” Mathis said. “It's just something I have to get used to because for over a decade I've been right there, right next to his side. He's been right there talking, joking and (we) formed more of a brotherhood than just teammates. So it's kind of weird, but it's something you have to get used to.”
Their numbers together, in retrospect, were fairly staggering: Freeney set the Colts' career record for sacks (107.5). Mathis ranks second with 91.5.
During their heyday, they fed off each other, taking advantage of the fact offenses might be able to double-team one of them (often Freeney) but not both.
The tandem underwent big changes last season when the Colts switched defenses, essentially turning the defensive ends into outside linebackers. Mathis took to the change more quickly than Freeney, who fought injuries as he became the “rush end.” Mathis moves into that role this year and he'll work with free agent signees Erik Walden (now wearing Freeney's old No.93 number) and rookie first-round draft pick Bjoern Werner.
"New is not always bad," Freeney told CBS Sports. "Change can be good, especially for me."
Mathis knows more eyes will be on his play and his production with Freeney out of the picture.
“I don't think anybody can put more pressure (on me) than I can put on myself,” Mathis said. “It's the first time that I'm the No.1 rusher, the lead rusher or whatnot. I put the pressure on myself more so than anybody else could.”
Mathis finished with eight sacks last season, a decent number but still the second-lowest since he became a regular player. Some of that could probably be attributed to the new system. He's bound to feel more comfortable the second time around with coach Chuck Pagano and defensive coordinator Greg Manusky.
Mathis has also stepped up his role, which increased last season, as a veteran leader on the team. Mathis, Reggie Wayne, Cory Redding and Antoine Bethea are the every down players who have the most veteran credentials.
“I love it,” Mathis said of being a team leader. “That means you've been around for a while, so that's a blessing in itself. You like the way the guys look at you. They kind of put the onus on me. They follow my tenacity or leadership.”
Pagano said he understands why Mathis would need some time to get used to playing – or simply being in the locker room – without Freeney.
Pagano reiterated that the decision not to re-sign Freeney after his contract expired was a business one that the Colts front office and staff had to make in what they thought was the best interest of the team moving forward.
“Those guys had a lot of time together, a lot of play time together,” Pagano said. “They built, as Robert said, a friendship, a brotherhood if you will. There's a certain comfort zone. One knew the other one was always going to be there.”
Pagano said he knows from being around football how the bond between Mathis and Freeney remains stronger than simply a uniform.
“We always talk about how this game will fade at some point for all of us,” Pagano said. “But the relationships will never fade. I know Robert and Dwight's relationship will never fade and that's something they'll have for the rest of their lives.”