Legitimate lefty ace and AL Cy Young contender Dallas Keuchel improved in a lot of ways over last season, which is impressive. His 2.91 ERA / 3.21 FIP / 3.20 xFIP and 3.8 fWAR last year did not leave that much room for improvement. He did it anyway. His strikeout rate went up (backed up by a higher whiff rate), his BABIP went down (little luck, little popup rate increase, little soft-hit rate increase), and his strand rate went up. He can be vulnerable to the long ball, but his absurd ground-ball rate of 61.7 percent (which is 2nd in MLB among qualified starters) ensures that not many balls are hit in the air in the first place.
Not only does he generate tons of grounders, but it is difficult in general to make solid contact. His career line drive rate of 18.6 percent is under MLB average, which was 20.9 percent this year. His soft-hit rate is above MLB average, and his hard-hit rate is below MLB average.
Since his grounder rate is so high, you would expect Keuchel to rely on his sinker; indeed, this is true. Though the velocity on the pitch is not high (90.5 mph average), he threw it almost 50 percent of the time in 2015. The other pitches Keuchel throws include a four-seam fastball (~7% usage), a changeup (~14% usage), a slider (~20% usage), and a cutter (~10% usage). Rounding errors bring that to 101 percent, but don't mind that.
Keuchel is predictable in how he will use his pitches. Early in the count, he'll throw his sinker. A lot. Against lefties, he's basically just sinker/slider. Sinker early, slider when ahead/two strikes. He'll mix in his four seamer as a change-of-pace pitch early in the count, but he won't do it that much.
Against righties, Keuchel involves the cutter and changeup a bit more. With two strikes, he still relies on the sinker the most, but the slider is just behind the sinker in terms of usage. The changeup is not that far behind.
As you would expect, righties hit Keuchel better than lefties. Lefties are basically useless against him, hitting .171/.198/.255 this year. However, Keuchel is just really good in general, so righties didn't fare much better at .228/.279/.330.
The best hope is to catch a four seamer. Batters hit .296 BA / .568 SLG against that pitch this year, and that's really the only one where a player can get some power.
In terms of location, he's relatively predictable. Against lefties, he'll stay almost exclusively low and away. Not surprising. Against righties, though, he can back-door his breaking stuff. Here is the zone plot of Keuchel's slider against both lefties and righties. You know exactly where it's going to go.
Keuchel will also throw his cutter inside to righties to hit the slimmer part of the barrel.
One trend to note - I mentioned that he relies on his sinker about 50 percent of the time. That has changed through this season. As the months have gone on, Keuchel has introduced his slider and cutter more and more at the expense of his sinker, which sat at about 40 percent usage in September. Those breaking pitches get more whiffs, for which Keuchel has sacrificed ground balls. As his whiff has increased through the months, his ground-ball rate has decreased.
What this means is that though his pitches might be a little predictable in terms of the count, they're not any easier to hit. Keuchel can mix and match to achieve the result he wants. He has the command to put the slider, his big whiff pitch, where he wants. It's quite a scary combination.
Keuchel has faced the Royals twice this year. In the first, June 30th in Houston, Keuchel shut down the Royals. He threw eight shutout innings while giving up seven hits and getting seven strikeouts. In the second, July 26th in Kansas City, the Royals got to him. He gave up five runs in six and two-thirds innings with 10 hits, a dinger, and five strikeouts. He is a scary pitcher, but the Royals can get to him.