Morrison will start at first base this season as the Mariners did not address the position in free agency, the Seattle Times reports.Morrison's was effective last season when he played, but health has been his biggest obstacles in recent years. He has not played more than 99 games in any of the last three seasons. The Mariners can play Dustin Ackley, Brad Miller or Willie Bloomquist at first when Morrison needs a rest, but they don't have a long-term answer should Morrison get injured again.