Milwaukee Bucks star Khris Middleton suffered a hyperextended left knee late in the third quarter of Milwaukee’s 117-103 loss to the Celtics at TD Garden and did not return, but initial signs are that the injury won’t cause him to be out for a lengthy period of time. “We’ll know more tomorrow, but I think there’s some hope that it’s not serious,” Bucks coach Mike Budenholzer said. “But you’ve got to weigh it and give it time.”