Jason Bay won't lose his starting job this week or likely even this month, but it doesn't mean the Mets left fielder is untouchable. Though the idea has not yet reached the discussion stage among team executives, a club official yesterday floated the possibility that if Bay is struggling six or seven weeks into the season, the Mets could explore other options, including a platoon in left. Bay is hitting .195 with no RBIs this spring after going 0-for-3 in the Mets' 9-2 exhibition loss to the Tigers yesterday. If the Mets were to consider a platoon, it could bode well for lefty-swinging Kirk Nieuwenhuis, who is slated to begin the season at Triple-A Buffalo.