PORT ST. LUCIE, Fla. — Kodai Senga may have the Mets’ first injury of spring training. Senga skipped Wednesday’s workout at Clover Park after complaining of “arm fatigue.” The Mets ace spent the afternoon with the trainers and manager Carlos Mendoza did not have any other information after the workout. “After his side session yesterday he came in experiencing some arm fatigue,” Mendoza said. “So he stayed inside and we’re taking a look at it.” Senga was with the trainers after practice and was unable to speak with the media. It’s not yet known whether he will undergo imaging on his arm. Arm fa…