Miami Marlins' Giancarlo Stanton holds his head after being injured in the 10th inning of a baseball game against the New York Mets at Marlins Park in Miami on Monday, April 29, 2013. (AP Photo/The Miami Herald, Joe Rimkus Jr.)MIAMI (AP) — Miami Marlins slugger Giancarlo Stanton expects to be sidelined for roughly a month because of a strained proper hamstring.