One of the oldest cliches in baseball is that pitchers have to establish their fastball. The average Major League pitcher throws their fastball about 60% of the time, and any deviation from that can get you labeled a junkballer.
Francisco Liriano, with the Pirates season on the line, told that cliche to go pound sand.
Here are his final pitch tallies for the night, per PITCHF/x.
Basically, Liriano swapped his fastball and slider usage, using the breaking ball as his primary pitch and using the fastball as his change-of-pace. Needless to say, it worked. Of the 44 sliders Liriano threw, 34 of them were strikes, and 13 of them were swinging strikes. That’s absurdly good; for context, he got four swinging strikes on his fastball and change-up combined.
And when they made contact, they generally pounded it into the ground. Opposing batters put Liriano’s slider in play nine times. One of those went for a single. Eight of those went for a groundout, including a double play.
Liriano’s slider is one of the best in baseball, and is clearly his best pitch. Rather than relying on his fastball as his primary pitch, Liriano threw his best pitch more often than the others. The result was not so bad. Maybe there’s something to going with your best weapon, rather than relying on a large number of straight pitches that hitters can actually put their bat on.
When you have a dominating out pitch, use it. Liriano does, and he did.