Johnny Damon -- My Wife's Pregnant ... With Our 7th Kid!!!

Big news for Johnny Damon ... the baseball star just told TMZ Sports his wife is pregnant with BABY #7!!!!

Damon was out in NYC for the "Celebrity Apprentice" finale when he broke the news ... telling us his wife Michelle is knocked up!

FYI -- Damon started having kids back in '99 when his first wife Angela gave birth to twins.

He married Michelle in '2004 ... they had a daughter in '07 ... another daughter in '08 ... twins (again!) in '12 ... and now she's with child again!

Damon clearly LOVES being a father -- and even had some retirement advice for Derek Jeter ... start procreating!!!