Hernández throws a fastball that has been clocked as high as 100 mph, although he does not rely entirely on overpowering velocity. Instead he often uses a two-seam fastball, which comes in just a bit slower but with more movement and sink as it approaches the batter. His repertoire of pitches also includes a hard curve, a changeup, and a slider, all of which he can throw extremely well (he avoided the slider early in his career because the team was concerned it might injure his arm). When at his best, Hernández can induce a steady procession of groundball outs and strikeouts, with very few balls being hit in the air.