Through the years, he has caught an impressive group of pitchers who have come through the system. He's been behind the plate for the likes of Josh Beckett, A.J. Burnett, Brad Penny, Carl Pavano and Dontrelle Willis.
Last season with the Marlins, he primarily caught lefties Scott Olsen and Willis.
Based on early indications in Spring Training, Treanor sees the new group of Marlins pitchers rivaling some of the most talented arms the organization has had.
"For the most part, the guys who were here last year, who had little or no big-league experience, I've seen them come into camp and really concentrate on something specific they want to work on," Treanor said. "Their bullpens have been really good. The maturity, you can tell they understand the game a little bit better, and what they need to do to get better."
Treanor added that some of the pitchers don't fully realize how good they can be.
The whole climate around the club is different now compared to 2006, when an abundance of rookies and inexperienced players came wide-eyed into Spring Training. Back then, everything was new for so many players. With only a handful of veterans around, the young players had to learn on the fly such basic things as how to travel, along with how to tip cab drivers and hotel workers.
Treanor was one of the few who could point the rookies in the right direction.
"I think that was huge for a lot of guys," Treanor said of their transition to life in the big leagues. "They'd never been on a chartered flight. They never had to tip guys [in hotels]. It was kind of shocking at first, but it was nice to see most of the guys asking questions and trying to figure it out. They were wanting to do the right thing."
Another enlightening experience was dealing with all the "firsts" for the baby Marlins. It's customary for players to receive the ball for initial accomplishments. Like when a player gets his first MLB hit, the ball is retrieved and tossed into the dugout as a keepsake.
On a team that played 22 rookies before the September callup period, balls were constantly being flipped into the dugout.
"At first, I was thinking maybe people were going to get drilled, because every other guy was getting their first hit," Treanor quipped. "They were stopping the game to throw the ball back. But a lot of the other guys on the other teams were classy about that stuff."
Learning the ropes in the big leagues is a process. There are codes of conduct and protocol to follow.
In 2004, Treanor felt fortunate to be taken under the wing of All-Star Paul Lo Duca, who was obtained in a July trade from the Dodgers. Lo Duca offered advice to Treanor, and the two quickly became friends.
Ironically, when Lo Duca was acquired, he replaced Treanor on the roster. And in dramatic fashion, Lo Duca's first at-bat as a Marlin came in a pinch-hit role. Lo Duca batted for Treanor, and in storybook fashion, he homered on the first pitch.
"Before that at-bat, he came up to me and said, 'Hey Matt, what's going on?' I hadn't really talked to Paul at all," Treanor said. "I got called up in September, and then the next spring, he was offering me advice and doing all the things you'd think a veteran would. The next thing you know, we're hanging out, having dinner and he's showing me what it takes to be in the big leagues."
Now the tables have turned, and many young players are seeking Treanor's advice.
"It's kind of weird," Treanor said. "When I first came up, guys were making millions of dollars, and they'd been in the big leagues, seven, eight, 10 years or whatever. Now, I only have 2 1/2 years in the big leagues, but I feel awkward like it's not my spot to [be a leader], like announce things after meetings and stuff like that. But if you look around the room, everybody has one year or something of experience."