Coach John Harbaugh, a football lifer not prone to hyperbole, is so impressed by the veteran pass rusher's physical and technical preparation that he believes he's "never seen a guy take care of himself any better" than Dumervil.
But the 31-year-old Dumervil admits he "wasn't as much [of] a pro" in Denver as he is now, the type who didn't realize "you can't just get up and go play football."
The transformation is so much a part of him now that rookie outside linebacker Za'Darius Smith, who watches his every move, can't picture a world where Dumervil wasn't so diligent.
"I never would have thought of it," Smith said "He's an older guy, and he prepares well with it. He gets ready for game situations as if it's his last. He takes every moment that he has [toward] being a great player."
"Give credit to the Ravens," Dumervil said. "At the end of my career [in Denver], I was banged up quite a bit, and I really didn't know how to take care of my body. Now things are a little different. I have a nice little routine and I feel good about the strength program here. I'm doing things necessary to be healthy. I think a healthy player makes a good player."
Since he's come to Baltimore, and especially in 2014, Dumervil has been both. Of his 90 career sacks, 26.5 have come in the two seasons he played with the Ravens, and he was one of three players the team sent to the Pro Bowl last season.
His 17 sacks tied a career high set in Denver in 2009. He returns there as someone whom the organization that watched him blossom into an All-Pro from the fourth round of the 2006 NFL draft might not recognize.
Sunday will be his second trip back to Denver as a player, his first since 2013 when the Broncos, as he described it, "beat us that year nice and good."
He said he hasn't talked to any of his former teammates about the game. His departure is clearly a sore subject, even if being with the Ravens has extended his career.
Dumervil had agreed to a restructured contract in 2013 after seven seasons with Denver, assenting to a $4 million pay cut, but a fax machine issue between his former agents and the team forced Denver to release him to ensure they wouldn't be on the hook for his $12 million guaranteed salary that year.
The Ravens brought him in as a complement to star outside linebacker Terrell Suggs, and he debuted for the Ravens with 9.5 sacks that year. Last season, though, was the best any pass rusher has enjoyed in franchise history, and he combined with Suggs for the most sacks by any pair in the NFL. Judging by how he has decorated his locker, that might not be his career high for long.
A white sheet of paper with the number 23 in black marker hangs in Dumervil's locker, representing what it will take to break the NFL's sack record. New York Giants Hall of Famer Michael Strahan set the record in 2001 with 22.5, and it's clear Dumervil has his sights set on that mark.
He's always used speed and technique to get by blockers — though listed at 5 feet 11, 255 pounds, Dumervil isn't as overpowering as Suggs. Even if he's coy about what they are, he comes into the season opener against his former team having prepared even more tricks to get after quarterback Peyton Manning.
"I've been working on a few things," he said with a smile.
"You always want to work on your arsenal, add some things," Dumervil added. "I'm a student of the game. I like to study pass rushes. It's one of those deals where you can always get better. There's always room for improvement."
Harbaugh said that doesn't only occur during business hours in Owings Mills.
"He works individually, when he gets home," Harbaugh said. "He's always studying pass rush. He's studying the defense. He wants to be a good dropper [into coverage]. He wants to cover as well, even though that's not what he's known for. He wants to be good at every aspect of football."
His role with the Ravens has mostly been limited to that of a pass rusher, though, with Courtney Upshaw typically starting and playing during passing downs. Dumervil has played over half the defensive snaps for the Ravens since he's been here, but his limited usage and steady role has allowed him to focus more on the pass rush.
Smith marveled Friday at the recall Dumervil has for the offensive tackles he has faced, former Denver teammate Ryan Harris chief among them. He'll formulate a plan of attack for each individually, which defensive coordinator Dean Pees said makes it impossible to predict which of his tricks he'll try to use to get around them.
And up against an offensive line featuring rookie Ty Sambrailo on the left side of the offensive line — Suggs' side — and two new starters on the interior, Dumervil has the doubly difficult task of facing Harris and chasing a quarterback, Manning, who gets the ball out quickly.
"He's one of the best pass rushers there is," Pees said, "so I'm sure he has it figured out."