For 14 seasons now, Yadier Molina has been a rock behind the plate for the St. Louis Cardinals. He's a two-time World Series champion, an eight-time All-Star, and an eight-time Gold Glove winner. Twice he's finished in the top four of the NL MVP voting.

And in three years, the Cardinals will have to replace him.

Monday the 35-year-old Molina confirmed he is planning to retire at the end of his current contract. The three-year extension he signed last March will pay him $20 million per season from 2018-20. After that, Molina will hang 'em up.

Molina's game has started to slip the last few seasons, which isn't terribly surprising for a catcher at his age and with all those innings on his legs. He hit .273/.312/.439 (96 OPS+) last season, down quite a bit from his 2011-13 peak, and his throwing arm is merely very good rather than otherworldly great now.

That said, Molina remains one of the game's top backstops, especially on the defensive side. He's a quality framer, he is still an above-average thrower, and he works exceptionally well with pitchers. The Cardinals have long considered anything Molina gives them at the plate a bonus, and I suspect that is still true today.

MLB: St. Louis Cardinals at Pittsburgh Pirates
Yadier Molina will call it a career after the 2020 season. USATSI

Now that the Cardinals know when Molina is planning to retire, they can begin the process of grooming his long-term replacement. Top catcher prospect Carson Kelly -- ranks Kelly as the 32nd best prospect in baseball -- is essentially big league ready right now. He's had multiple cups of coffee the last two years and hit .283/.375/.459 with 10 homers in 68 Triple-A games in 2017.

Kelly started his pro career as a third baseman before moving behind the plate, and there's been some speculation the Cardinals will give him more reps at the hot corner going forward. That would allow them to carry Kelly on the roster, get him into the lineup more often, and have him serve an apprenticeship under Molina the next few years.

No matter how the Cardinals replace him, they will lose one of the best players in franchise history in three years when Molina calls it a career. You can be sure the team wants to do everything possible to win while he is still behind the plate.