Serbian big man Nicolas Mitrovic, who committed to Cal in early March and reclassified into this year’s high school graduating class, signed with the Bears on Friday. Mitrovic, who played this season at Cambridge Arts, Technology and Science in Massachusetts, will join the Bears’ coming class of players — currently four transfers and two freshman — next fall. Cal lists him as a 7-foot post player but various website cite his height as anywhere from 6-foot-10 to 7-feet and have him at either power forward or center. He was originally projected to be part of the 2027 high school class, but will graduate early and join the Bears next season. “Nicolas is one of the most exciting young big men in the country,” Cal coach Mark Madsen said of Mitrovic. “He has tremendous skill for his size and length. This makes him a true threat inside and out on both ends of the floor. We are ecstatic to add Nicolas to the Cal family!” Mitrovic chose Cal over Seton Hall, UNLV, La Salle and Pepperdine.…