Caratini can reportedly earn additional performance bonuses.
Caratini is a .236 career hitter with 38 homers and 171 RBIs in seven major league seasons with the Chicago Cubs (2017-20), San Diego (2021) and Milwaukee (2022-23).
Yainer Díaz is expected to be the Astros' starting catcher next year, and the agreement with Caratini could mean Houston won't re-sign Martín Maldonado. The 37-year-old has been with the Astros since 2019.
"I've been talking to Yainer once a week," new manager Joe Espada said Monday. "We're going to do some things in January leading into spring training to prep him for spring training. I don't want us to get to spring training and start from scratch.
"So this is going to be starting right now having conversations about our staff, how to attack certain lineups, things that we know that we can help him with, receiving, throwing."
The Associated Press contributed to this story.