Alex Rodriguez says the Mets are going to be SUPER HAPPY with their new manager, Carlos Beltran ... telling TMZ Sports he thinks the guy is "a baseball savant."
"The Mets are going to love him," A-Rod says.
New York has stumbled the last few years with Mickey Callaway and Terry Collins running the dugout ... but Rodriguez seems convinced 42-year-old Beltran will turn things around next year.
Of course, A-Rod is a bit biased -- dude played with Carlos for a few years with the Yankees earlier this decade -- but he swears the ex-outfielder will kill it with the Mets.
"Love Carlos," Rodriguez says. "Great hire. Great person. New Yorker. His wife, Jessica, lives right here in the city. And, he's a baseball savant. I think the Mets are going to love him."
As for Beltran having NO managing experience heading into the gig ... Rodriguez says he has zero concerns about growing pains, telling us, "He'll do great, he'll do great."
By the way, Rodriguez has some new beginnings going on this week too ... he was out in NYC promoting his new show, "Back In The Game," which debuts Wednesday night.
Rodriguez tells us the CNBC project is all about coaching and mentoring former athletes and celebrities to try to get them out of a rut ... kind of like what Beltran is tasked with doing for the Mets!