Liriano's ERA currently stands at 5.06, a lot of which is still fallout from his atrocious start to the season. He's been better than that, but not markedly better, with a 4.43 FIP and 4.26 xFIP. The decrease in strikeouts and uptick in walks are still holding him back significantly in this regard; in addition to a drop-off of nearly two K/9, he's walking more than two batters more. In the month of June, he posted a stellar 27:7 K:BB ratio, but he's walked almost the same number of batters in only two July starts. I don't have the savvy about pitching mechanics or the knowledge to dig deep into Pitch F/X to explain if he's somehow regressed mechanically or has changed his release point from what he was doing in June, but it's somewhat troubling that the control issues from earlier seem to be resurfacing. The whole "should Liriano pitch to contact" debate and the discussion of what that really means aside, Liriano certainly needs to avoid giving up as many free passes if he's going to regain his dominance, as he hasn't been able to compensate for wildness by missing more bats. It seems obvious, but it's true. To be fair, three less-than-great starts recently is still a small sample size and all pitchers have off nights, but it highlights the fact that Liriano hasn't been consistent, and thus not currently the pitcher that most Twins fans would trust at this point in the season to get a crucial win (I have to think that would be Baker, but feel free to disagree with me on that one).
Digging farther into the numbers, there are a few other things that stand out. On the positive side, Liriano's swinging strike percentage remains excellent at 12.2%. Liriano posted a 12.4% in the 2010 campaign, and is only surpassed by Michael Pineda this year (12.5%) in all of baseball. If he keeps this up, it's very possible that we'll see the strikeouts start to come around again. Contrary to last year though, and perhaps contributing to the lack of K's, is that his O-Swing percentage (percentage of swings generated on pitches outside the strike zone, or, in general, batters "chasing") is down from 34.4% last year to 27.9% this year. The effect that stat is really having though is purely speculative; for comparison, Liriano's 2006 mark was only 27.5% (although that year he did put up a stunningly awsome 16.4% swinging strike percentage). If I had to guess, I'd say that more batters this year seem to be laying off the slider, a fact which may be backed up by the fact that last year his slider was worth 19 runs above average, whereas this year it's only been worth 5.6. While still an effective pitch, this decrease in results from the slider, in turn, may be causing him to favor the changeup more (4% increase from last year). That said, I'm not sure that throwing the slider more is any sort of answer, I'm more just pointing out things I'm noticing in the numbers.
Lastly, I'll discuss the concept of keeping the ball on the ground. We've already seen that he's missing fewer bats and thus has been relying more on balls in play to get outs, so looking at what types of balls are being put in play is important. In general, the more ground balls the better for a pitcher. Even though ground balls have a higher BABIP that fly balls, the biggest thing is that ground balls can't leave the yard. Last year, Liriano posted a career-high 53.6% ground ball rate, and I think that that was a positive contributor to his success, particularly in the small amount of home runs he gave up. This season, his GB rate has fallen off to 47.9%, and my gut wants to tell me that this is somehow related to his decreased success. However, with Liriano, it's not quite that simple on a game-by-game basis. For someone like Nick Blackburn, who isn't able to generate many strikeouts, there's usually a pretty good correlation between getting more ground balls and quality starts. For Liriano, though, that surface-level analysis doesn't play out. Case in point: during the game against the Royals (which brought the pitch-to-contact debate to a head) Liriano generated 15 ground balls and only 3 fly balls. Some of those ground balls (6 in fact) just happened to find their way through the infield in the fourth inning. Conversely, during his no-hitter, Liriano generated 11 fly balls compared to only 9 grounders. On May 22nd versus Arizona, his ratio was even worse with 12 fly balls to 5 grounders, yet he escaped with only two earned runs. And lastly, on July 6th versus Tampa, his GB:FB ratio was 2:9 yet he surrendered 5 earned. All of this goes to say that as a season-long trend, it could be that less grounders might equal less success, but it's harder to make sense of that when you dig into individual examples.
I started this piece intending to pick out concrete things that Liriano needs to do to find more consistency and get his season back on the right path, but along the way I think I found more questions than answers. Does he need to throw more strikes? Does he need to throw the slider more often and more effectively? Does he need to generate more ground balls? He certainly needs to cut down on the walks, and if batters aren't chasing as many balls outside the zone, he may have to find a way to compensate for that to avoid walking batters and running up his pitch count. However, for Liriano, throwing more strikes shouldn't mean turning into Blackburn or Buerhle; it should mean finding good locations within the zone early in the count to set up his out pitches. Regarding throwing the slider more, I wouldn't suggest that's any sort of answer. The reason that he hasn't been throwing it as much could be that it hasn't been as effective - I'll have to come back to why exactly that is, but there has to be a reason. And regarding keeping the ball on the ground, well, that's a little more complicated than I thought but I still would generally suggest it's a good idea, if only to try to keep home runs in check. (Liriano's HR/FB rate last season was 6.3%, which was certainly a bit luck-driven, but generating grounders certainly contributed). All of this might just be a fancy way of saying "pitch better," and the haste with which I tried to get this out means I probably left plenty of gaps in my logic. But if Liriano can regain the excellent command he exhibited last year (and stretches of this year), it will go a long way towards helping him return to dominance. With an in-form Liriano and a healthy, consistent Scott Baker, the Twins will have a 1-2 punch that could push them into a playoff spot.