Whitley underwent an MRI exam and other tests early Friday and Manager Joe Girardi expressed concern that he may need Tommy John surgery. Chris Capuano, who is coming back from a quadriceps injury, is expected to take Whitley's spot in the rotation.
The San Francisco Giants plan to activate right fielder Hunter Pence on Saturday. Pence has been recovering from a broken left forearm. . . . Washington Nationals right-hander Doug Fister was placed on the 15-day disabled list because of right forearm tightness after giving up seven run in two innings Thursday to the San Diego Padres. . . . Houston Astros right-hander Lance McCullers Jr., who had an 0.62 earned-run average in double A, will make his major league debut on Monday night in a start against the Oakland A's at Minute Maid Park, General Manager Jeff Luhnow announced.