Hernandez has a 5.5 WARP this year
Lowell has a 2.2.
Dice K is - 0.8.
Last year, Lowell was a defensive ace, which was worth up to two wins a season. That's a big chunk of his value being taken away.
Dice-K was better than Felix Hernandez in 2008, but that's because he managed to have a ridiculous amounts of stranded base runners.