"I'm so high energy," Mathis said. "I've always played that way. What I see now is that I was speeding it up more than I needed to; trying to do so much, it ended up hurting me.
"Something I've started to learn is that less is more with everything."
Whether it's hitting, catching, guiding a pitching staff or throwing out baserunners, Mathis is finding that by controlling his emotions and taking a more methodical approach, he's getting better results.
Competing with best buddy Mike Napoli for playing time seems to be bringing out the best in Mathis, whose quality work behind the plate during the second half of 2007 was pivotal in the Angels' drive to a third American League West title in four seasons.
The Angels demonstrated faith in Mathis when they dispatched Jose Molina to the Yankees last July, and he rewarded them.
"I don't think we have to lay down a template on how much both guys are going to play," manager Mike Scioscia said. "I don't think we need to rank them. They've both shown they have the ability to play at a very high level.
"The bottom line for these guys is winning. Although they'd like to be that guy who catches 140 games, more important to them is our team."
When Mathis pressed and struggled in 2006 and was sent to Triple-A Salt Lake, Napoli seized the job. But when injuries to his shin and hamstring hobbled Napoli throughout the second half of '07, Mathis was summoned -- and this time he was ready.
The Angels were 34-18 in games started by Mathis, whose 3.89 ERA was the best among Angels catchers.
"Jeff's defensive numbers, particularly in the second half, I would put up against anybody in baseball," Scioscia said. "We were very confident when we traded Jose that Jeff would do the job. I think he learned how to relax and play the game before we got to that point.
"The way he handled himself behind the plate last year was something we needed to see. He was an important piece of what we did in the second half."
A late-season slump left his average at .211, but Mathis came to camp determined to prove he was better than that.
Staying back and slashing line drives to all fields, Mathis -- who turns 25 on Opening Day, March 31 -- has been an offensive plus in Cactus League play, hitting .273 with six walks against seven strikeouts. That's significant improvement in plate discipline for a guy who had 15 walks and 49 strikeouts in '07.
"I'm laying off some pitches, getting some good counts," Mathis said. "I'm not chasing everything, getting myself in bad counts. That's part of slowing it down, not getting ahead of myself."
His arm, always an asset, was somewhat erratic in 2007. Here, again, Mathis feels he has corrected a flaw by staying within himself, turning it into a weapon.
"He has an arm that can control any running game in the league," Scioscia said. "We've seen it in the Minor Leagues. Last year in the Major Leagues, he wasn't as consistent, but he's made some adjustments."
Controlling his throwing motion has improved his accuracy.
"My focus is on getting my feet in the right spot," Mathis said. "Trying to be as quick as I can be to second, I wasn't putting myself in the best position to throw. Being less anxious has made a big difference."
An acclaimed high school quarterback in Marianna, Fla., Mathis played in a state championship game in 2000, and he was recruited by Florida State to run its offense.
On superscout Tom Kotchman's recommendation, Mathis was signed as a first-round pick (33rd overall) in the 2001 First-Year Player Draft.
Mathis' background as a take-charge quarterback has been evident in his commanding presence behind the plate. The positions are similar in that everything starts with their signal-calling.
Angels catchers are entrusted with the responsibility of calling every pitch without direction from the dugout, something Scioscia considers critical to the pitcher-catcher relationship.
"That's how he brought us up through the Minors," Mathis said. "He wanted us to figure out how to call a game.
"Just the other day, Sosh was saying that a lot of people refer to the catcher as the quarterback on the field, but he's really more like a safety, putting everyone in the right position."
Slowing offenses down, a resourceful, tough-minded catcher can hasten a team's ascent. Having figured that out, Mathis has cemented his position as a rock in the Angels' foundation.
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.