Giancarlo Stanton will undergo arthroscopic surgery on Saturday to deal with a "loose body" in his right knee, and is likely to miss a month. It's a tough break for the Marlins young slugger, who will now be forced to miss next week's All Star Game and Home Run Derby. Bryce Harper has been named as Stanton's replacement in the game, making it so the Marlins will not have a representative active in the contest.