By Tim Healey/DFP StaffThe Boston University men’s hockey team finally has a number-one goaltender, but not by choice.Freshman Matt O’Connor is out indefinitely with spontaneous pneumothorax and is expected to make a full recovery, according to a team source. Spontaneous pneumothorax is a collapsed lung that happens with no apparent cause.O’Connor is in the hospital as of Monday evening. There is no information available on a recovery timeline.”A small area in the lung that is filled with air can break open, sending air into the space around the lung,” according to the U.S. National Library of Medicine. Tall, thin people are more likely to suffer collapsed lungs.The 6-foot-5, 201-pound O’Connor has posted a .910 save percentage and 2.86 goals-against average in 19 games (18 starts) in his rookie campaign.The news comes two days after freshman Sean Maguire started two games in a weekend for the first time this season. After making 49 saves and one goal in a win against the University of Vermont Friday night, Maguire gave up four goals the next night, just hours after finding out he would make the start.