The swimmer who owns 18 Olympic gold medals in middle and longer distance races is going to try sprinting. Phelps will compete in the 50-meter freestyle at the Arena Grand Prix on Friday, except he plans to swim his morning heat using a butterfly stroke. [...] competing in the 50 free are former Olympic gold medalist Anthony Ervin, Nathan Adrian, and Michael Andrew, a 15-year-old from Lawrence, Kan., who has already broken over 30 national age-group records. A relaxed Phelps was smiling Thursday after swimming his first race since the 2012 London Olympics, even though he lost to longtime rival and friend Ryan Lochte. Natalie Coughlin took her own extended break after the 2008 Beijing Olympics. Phelps' times were easily good enough to surpass the qualifying standard of 54.79 for the U.S.