Johnny Damon is sending a huge warning signal to the AL's top dogs ... telling TMZ Sports if the Yankees and Astros let Boston climb into the postseason -- the Sox might just win it all!!!
We got Johnny out in NYC this week and had to ask some baseball questions ... and that's when the 2-time All-Star told us teams NEED to be afraid of the Red Sox's potential.
"If they can somehow get above Tampa and make the playoffs, they're going to be scary," Damon says.
And, if you think Johnny is just blowin' smoke because he's a Sox legend ... he ain't -- he tells us he's still got some bitterness toward the way he left the team after the 2005 season.
"Boston and I, it was a little like a divorce," he says.
Johnny tells us the Red Sox are legit this year ... and if they had actually signed a closer in the offseason, he thinks they'd be much closer to the Yankees in the AL East standings right now.
Still, Damon says he thinks the Astros are the favorite for now ... saying when he watched Justin Verlander pitch earlier this week -- he didn't seem hittable!!!
By the way, Damon also tells us he hasn't spoken to his good friend and former teammate David Ortiz since he left the hospital ... but he made sure to send his well wishes to Big Papi.