After missing only six regular-season games last season and one this year up until last night, perhaps it was inevitable that Kevin Garnett’s aging body would experience a complication. The Celtics center missed last night’s 105-88 win at the Garden against the Charlotte Bobcats due to what trainer Ed Lacerte diagnosed as a strained adductor in his lower left leg. Coach Doc Rivers, who was loathe to talk too much about this temporary loss of his defensive leader before the game, had no idea if the injury would keep Garnett out of tomorrow night’s matchup with the Miami Heat at the Garden. “I honestly don’t know,” Rivers said. “I haven’t looked that far ahead. He’s not here. He may come, but I told him he didn’t have to.” Though Garnett participated in a good portion of Friday’s practice, Rivers wasn’t happy with his movement. Garnett had been struggling with his shot prior to Wednesday’s win over the Toronto Raptors (7-for-29 in two games against the Oklahoma City Thunder and Charlotte), president of basketball operations Danny Ainge said he had no idea whether the mini-slump was the result of leg trouble.