The calendar has flipped to May, so it's time to assess your fantasy players. Players who aren't performing may force us to adjust our expectations moving forward rather than assume positive regression is coming.Of course, we don't want to cut bait on a superstar who goes supernova for five months, either. It's a delicate balancing act.Three fantasy underperformers thus far are Josh Hader, Corey Seager, and Corbin Carroll. Will they recover their fantasy value or should managers sell them at a ...