First, let's look at the good. In his last two starts he has limited the walks, while racking up strikeouts, resulting in a 5.67 strikeout-to-walk rate. In addition to the juicy walk and strikeout rates, he is keeping the ball on the ground with a 48 percent groundball rate. In terms of controllable stats, Liriano has done an excellent job in his last two starts. From a stuff stand point, he has been very impressive as well. His four-seam fastball and sinker averaged just a bit over 92 mph in his May 30 turn, and were up a few more ticks to just over 94 mph in his June 5 start hitting as high 96 mph. His change-up is sitting at a velocity nearly 10 mph slower than his heater. It hasn't been a pitch he has used often, having thrown it only 11 times in the two starts combined, and it hasn't been a big swing-and-miss offering, with just one whiff, but it is a pitch that he can use to change speeds and keep hitters off balance. His truly filthy pitch that he has used to dominate batters is his slider. He has thrown the pitch 70 times in his last two starts, giving him a 38 percent usage rate in that time span. Of those 70 sliders, 21 resulted in whiffs, or in other words, an astonishing 30 percent drew empty swings. Beyond the 21 whiffs, he has added another 32 strikes. In all, 53 of 70 sliders were strikes, good for a 75.7 percent strike rate. People who are fans of visual proof should check out the gif in Sam Miller's fun piece at Baseball Prospectus. So what isn't there to like?
The first, and most obvious, is that it is only two starts. Many pitchers have looked good in back-to-back starts. Also, if you have been observant, you've noticed that I haven't named his opponents. Liriano faced the A's and Royals in his return from the bullpen. The A's rank 28th in runs scored in the majors, and the Royals rank 25th in runs scored. That's two really bad offenses. Beyond not scoring runs, Paul Sporer pointed out on Twitter that those two offenses struggle against left-handed pitching. With those facts in mind, there are reasons to tread cautiously in regards to Liriano. He has yet another favorable matchup on Sunday against the Cubs, who rank 27th in runs scored and are hitting .223/.291/.318 as a team against southpaws. He's a strong matchup play who is a fine wait-and-see bench option given his previous success, electric stuff, and his recent play.