"I felt really emotional when I found out [that I was starting]," Rosario said. "I was really happy. I've been waiting for this opportunity and I just went out there and did the job."
Following an RBI single as a pinch-hitter in his first big league plate appearance Saturday, Rosario, 29, lined a base hit to right his first time up Sunday. Regarded widely as a defensive-minded catcher, the Cardinals were glad to see Rosario's first major contributions come with the bat.
"He's a kid that's been around the Minor Leagues for a while and everybody kind of labeled as just this defensive player," Matheny said. "He's put together a nice offensive season. It's nice to see that the first contribution he has is offensively."
Coming into the season, Rosario was a career .235 hitter with a .287 on-base percentage and a .303 slugging percentage. With Triple-A Memphis in 2016, however, Rosario earned his callup by batting .281 in 39 games. The biggest key to that turnaround, he said, was experience.
"The main thing is just having the experience that I've had in the Minor Leagues," Rosario said. "Knowing exactly what the pitchers are going to do to me. I can just attribute it to being a veteran in the Minors."
Saturday's debut was a personal thrill as he stood at his locker with the ball from his first hit resting behind him, and the weekend series stood as the culmination of 11 long years down on the farm.
"The hardest part of my time would definitely to have to have been going up to bat and not getting the numbers I wanted," Rosario said. "I was having to go do it every day and wasn't getting those numbers, but I had to concentrate and still do my best."
Defensively, Rosario has made a mark throughout his career. Since 2006, the Domincan Republic native has thrown out 42 percent of attempted basestealers. In Spring Training with the Cardinals, the coaching staff took notice and then made the move to promote him when he was producing with the bat as well.
Rosario's time came to start in place of Molina, and he came through once again.
"Sometimes with a young player, it's almost even better not to give him the whole night to think about it," Matheny said. "Just show up ready to play every day and hopefully your name will be in there when the bell rings and the first pitch starts."