Jose Canseco is taking the old adage "talk sh**, get hit" for real ... 'cause just hours after Logan Paul made a sex joke about his daughter -- the ex-MLB star said he's dead serious about fighting the YouTuber!
If you missed it, just one day after Jake Paulruthlessly KO'd Nate Robinson in their celeb fight over the weekend ... Jose threw his name into the hat to be one of the Paul brothers' next scraps.
"I will fight anyone of the Logan Brothers," Jose said, "they have enough for anyone with any type of talent yet or fighting skills."
Logan -- who used to date Jose's famous model daughter, Josie -- saw the tweet Monday ... and issued a SAVAGE response.
"no problem," Logan wrote, "i love smashing cansecos."