This doesn’t sound promising: Mets left fielder Daniel Murphy is flying to New York tonight from the Arizona Fall League for an MRI exam Thursday morning on his ailing right knee. Murphy felt discomfort in the knee during pregame batting practice Nov. 11 and hasn’t played in the AFL since. Murphy, by far the biggest (and most pleasant) surprise for the Mets this past season, already has missed time in Arizona this fall due to a lacerated forearm suffered during the league’s “Rising Stars” game last month. Needless to say, the Mets will have their fingers crossed.