He might not be great in October, but Alex Rodriguez is CRUSHING IT in May ... 'cause the baseball star just sold his Miami Beach mansion for a $15 MILLION profit, TMZ has learned.
We know ... A-Rod has accepted a $30 million offer for his 19,861-square-foot Miami Beach estate ... the same property he purchased in 2010 for $7.4 mil.
After he bought the place, the NY Yankees star sunk an additional $7.6 million into building his dream home -- meaning his total investment was $15 mil.
The home is unreal -- an oceanfront palace with 9 bedrooms, 11 full bathrooms (plus 2 half bathrooms), a 4-car garage, state of the art security system with 16 cameras and a Zen garden.
Plus, it's on the same street as Matt Damon!
Rodriguez quietly put the place on the market in August 2012 and was asking for $38 mil -- but ultimately, he decided to settle for a measly $30,000,000. Bummer ...
So who bought the joint? Unclear at this point ... but sources tell us the buyer is a celebrity who lives in Palm Beach.
Stay tuned ...