Michigan State bolstered its secondary on Friday with the commitment of transfer portal safety Nikai Martinez, a 13-game starter in secondary last season. A 5-foot-11 safety, Martinez tied for the team lead in interceptions at UCF last season and ranked fifth among UCF defensive players with 54 tackles. Martinez is one of five transfer portal defensive backs added by Michigan State since the end of spring football. He is the second portal safety addition for the Spartans, who brought Aveon Grose in mid-year. The Spartans also added Legond Cavazos (North Carolina) and Ed Woods (Arizona State) a…