New York Yankees slugger Giancarlo Stanton is uncertain for opening day because of chronic tendinitis in both elbows. Yankees manager Aaron Boone made the announcement as position players reported ahead of the first full-squad workout Monday. Asked whether it could impact Stanton’s availability for the March 27 opener against Milwaukee, Boone responded: “Tough to say.” In addition, outfielder Trent Grisham pulled a hamstring a few weeks ago in training but is running at close to full speed.