As Monday morning’s shootaround wound down, Lauri Markkanen showed off soccer skills his professionally playing brother might’ve enjoyed, juggling a ball with his feet several times before burying a 3-pointer. By Monday night, Markkanen had landed on the inactive list for the first time since missing the first three exhibition games. In both instances, back spasms sidelined the rookie forward. Markkanen also experienced back issues while playing for the Finnish national team in the EuroBasket tournament over the summer, though he missed no games. Coach Fred Hoiberg downplayed any long-term concerns, citing how Markkanen participated in the shootaround. But three flare-ups in such a short span isn’t ideal. “He got over it very quickly (in both previous cases),” Hoiberg said. Markkanen, 20, said this summer was the first time he experienced back pain. The Bulls have made clear all season that not overburdening Markkanen is a priority. He’s averaging 30.7 minutes. “He just had a little soreness and we’re taking the cautious approach,” Hoiberg said. “It has not been a big issue.” Workout wows: Celtics coach Brad Stevens’ voice oozed respect when asked about Markkanen, whom the Celtics worked out before the draft.