James Jackson, the Michigan-based trainer, was arrested on Wednesday after an altercation just outside the stable gates at Great Lakes Downs, according to a spokesman for the Michigan Horse Racing Commission. Dominic Perrone, the commission spokesman, said Jackson, the fourth-leading trainer at Great Lakes Downs and a perennial leader in the trainer standings at Michigan tracks, was arrested by Fruitport Township, Mich., police after a fight, though he said he had few other details. "There was a baseball bat mentioned" in the report, Perrone said. Efforts to locate Jackson were unsuccessful on Friday. Multiple phone calls to the Fruitport Township police-reports division were not returned.