The Cardinals and their catcher are finalizing a one-year, $9-million deal Monday night for the coming season, two sources confirmed.
Later Monday evening, Molina shared a video of Cardinals highlights on Instagram and these two words: "I'm back."
The club confirmed the agreement, and a formal announcement is expected sometime Tuesday.
The contract does not include an option.
Molina, 38, and the Cardinals both felt they were close to an agreement before Molina went to the Caribbean Series to compete for Puerto Rico's representative team. The championship was Saturday, and Molina's return home spurred the final stages of his return to the Cardinals.