Homeless Man -- Found Guilty of Murdering Homeless Ex-MLB Player

The man who stabbed a former MLB player to death has been convicted of 2nd degree murder in a L.A. courtroom ... TMZ Sports has learned.

Rod Craig -- who played 4 seasons in the league back in the early '80s -- was living on the streets back in 2013 ... when he tried to stay at a homeless encampment but was turned away by other transients.

According to investigators, 55-year-old Craig tried to kick a dog as he left the encampment ... infuriating several people who chased after him and attacked ... with one of attackers stabbing Craig in the chest.