[ATTACH=CONFIG]1303[/ATTACH]Francisco Liriano’s first six starts of the season were nothing short of disappointing.

With plenty of raw talent, the Twins potential rotation leader failed miserably, throwing 26.2 innings, allowed 37 hits (six of which were home runs), posted a terrible 21-to-19 strikeout-to-walk ratio and failed to pitch into to the sixth inning in all but one start.

In that time, Liriano was drastically out of whack mechanically and the coaching staff had even tried to recreate his spring training success by getting him to throw his four-seam fastball more than his two-seamer which he struggled to command. The changes did not keep him from derailing and a shift to the bullpen would be required.

After several outings in the ‘pen, injuries and perhaps a need to inflate his trade value necessitated his return to the rotation. Even though the team’s record in those four starts may not reflect it (1-3), Liriano has been a better pitcher during this more recent stretch. He’s worked 23.2 innings (completing six innings in all but one start in which he fell one out shy of the mark) and has allowed just 12 hits to go along with a much improved 29-to-10 strikeout-to-walk ratio.

One of the main reasons for this subtle rejuvenation is that he has increased his slider usage.

In the past three years, Liriano has had one of the game’s best sliders. According to Fangraphs.com, since 2010 Liriano’s slider has been “worth” 23.6 runs above average, making it the eighth most valuable slider in that time. However, he was encouraged to throw his two-seam fastball more often in attempts to get more quick outs – a ground ball here and there – to avoid getting into deeper counts like most strikeout pitchers do.

So, during his first stint in the rotation this year (April 1 – May 7), Liriano favored the two-seam fastball, throwing it 52% of the time and, of those, threw 56% for strikes – a good not great rate. Because of favoring his two-seamer, he threw his slider just 26% of the time in those six starts. In his second stint in the rotation (May 30 – Present), Liriano has leaned more on the biting slider, mixing it in now at 38% of the time.

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[TD=colspan: 4]Francisco Liriano – Slider Usage (2012)[/TD]

[TD]Two-Seam Fastball

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What’s more is that not only is Liriano using the breaking ball more frequently across the board he is also using it quite a bit to start off each batter in efforts to get ahead of opponents. One of Liriano’s shortcomings these past two years has been his inability to get ahead of hitters. In fact, of starters who have thrown a minimum of 150 innings since 2011, Liriano’s 51% first-pitch strike rate was the lowest in baseball. Not surprisingly, Liriano mainly threw his two-seam fastball on the first pitch and 62% of the time in his first six starts. Meanwhile, in his second go round, he has increased the amount of slider’s he has thrown (from 22% to 36%) and reduced the amount of two-seamers (from 62% to 38%). Because his slider has a much higher strike rate than his fastball, Liriano has found himself ahead in the count more in these last four starts.

The change in his pitch distribution has led not only to more strikes but also more ground balls. Liriano’s slider is a ground ball manufacturer and in his first six starts, he exercised a GB/FB split of 0.69, meaning he was inducing more fly balls than grounders (as seen in his six home runs allowed in that time). More recently, that batted ball ratio has increased to 1.00 GB/FB which means the amount of grounders has grown (and he has allowed just one home run in those four starts).

What we are likely seeing is Liriano upping his value from absolute zero to something that could bring the Twins a decent prospect in return if he continues this performance and the Twins decide to move him. Watch for Liriano to throw more slide pieces in tonight’s start again Pittsburgh.

Thanks, Parker. Excellent analysis as usual.