Johnny Damon is going to bat for fired Red Sox exec Dave Dombrowski ... telling TMZ Sports, "Dombrowski is a very good GM, very honest."
Boston made the shocking move just a few days ago to can their team's president of baseball operations -- just 10 months after he won the World Series.
Reporters out in Beantown are perplexed by the move ... and nobody seems to have a definitive answer as to why the dude was fired after having so much success since he was hired in 2015.