Sylvester Stallone and Jennifer Flavin are putting their Hidden Hills estate on the market ... TMZ has learned, just 9 months after they bought it.
Real estate sources say Sly and JF listed the place Monday for $22.5 million ... they bought the house back in March for $18.2 million.
The home is 10,460 square feet with 4 bedrooms and 6.5 bathrooms ... it comes with all the bells and whistles, including a pool, horse barn and stables, plus a riding arena.