Johnny Damon is going to bat for Donald Trump ... saying toward the end of his baseball career -- he and his teammates were straight-up scared to go out on the town in Baltimore.
Of course, Trump has found himself in hot water this week for comments he's made about the Maryland city -- ones in which he called Baltimore a "rodent-infested mess."
Damon says he thinks Trump's choices of words were a little harsh ... but he tells TMZ Sports he agrees with 45 -- saying back when he played in the MLB, he didn't love hitting the road there.