AaronGleeman.com

Francisco Liriano has reemerged as an elite pitcher this year and his latest masterpiece came Friday night against the Braves, with 11 strikeouts and zero walks in eight innings of one-run ball. His gem versus Atlanta marked the second straight start in which Liriano has allowed just one run while racking up double-digit strikeouts, and overall this season he's 6-3 with a 2.90 ERA and 87-to-21 strikeout-to-walk ratio in 80.2 innings spread over 12 starts.

Now four years removed from Tommy John surgery Liriano has clearly re-established himself as an ace, but because he was the ace prior to going under the knife the temptation will always be there to compare what he's doing now to the 2006 version that eviscerated the league as a 22-year-old rookie. Thanks to abundance of information available at Fan Graphs, we can get a pretty good idea of how Liriano in 2010 stacks up to Liriano in 2006.

Let's start from the top, with his fastball:

FASTBALL          2006     2010
Velocity          94.7     93.5
Percentage        43.6     50.7
Runs per 100     +0.13    +0.50

Liriano in 2006 threw his fastball an average of 94.7 miles per hour, but his velocity has dipped to 93.5 miles per hour this season. While that still ranks seventh in the league, a decline of 1.2 miles per hour is a significant drop in velocity. However, despite Liriano's fastball being slower he's thrown it 16.2 percent more often and the pitch has also been more effective, rating 0.50 runs above average per 100 offerings compared to 0.13 runs above average per 100 in 2006.

In other words, Liriano's fastball has gotten worse but he's gotten better at throwing it, which is natural for a pitcher as he gains more experience and also a credit to the work he's done on the long road back from surgery. Obviously it would be great if Liriano threw 95 mph again, but having better command of the pitch at 93.5 mph can actually be even better. Now let's take a similar look at his slider:

SLIDER            2006     2010
Velocity          87.7     85.0
Percentage        37.6     32.6
Runs per 100     +3.47    +2.71

Surgery cost Liriano even more velocity on his slider than his fastball, with the pitch going from an average of 87.7 mph in 2006 to 85.0 mph this year. Not only did his 87.7 mph slider lead the league in 2006, no one else even cracked 87.0. This year his slider velocity is 13th in the league and unlike with the fastball he hasn't been able to compensate by throwing it better. He's relied on the slider 13.2 percent less and the pitch has been 21.9 percent less effective.

Of course, less effective is a relative term. His slider has gone from +3.47 runs per 100 pitches in 2006 to +2.71 runs per 100 pitches this year, which is a big drop. Yet even at 21.9 percent less effective than it was before surgery Liriano's slider has been the second-best in the AL. That shows just how devastating his slider was in 2006, but also that, as Chipper Jones put it after facing him Friday, he still throws "some disappearing" and "Randy Johnson-type" sliders.

CHANGEUP          2006     2010
Velocity          83.5     84.8
Percentage        18.7     16.7
Runs per 100     +2.82    -0.99

Liriano's changeup was underrated in 2006 as everyone focused on his mid-90s fastball and ridiculous slider, but it ranked as one of the best in the league at +2.82 runs per 100 pitches. Since coming back from surgery Liriano's changeup velocity has actually risen by 1.3 mph, but that's not a good thing and when combined with a 1.2 mph decline in fastball velocity equals a much less effective weapon. In fact, his changeup has gone from great in 2006 to bad in 2010.

In terms of individual pitches, Liriano's fastball is slower but ultimately more effective, his slider is slower and less effective but still an incredibly dominant offering, and his changeup is faster but significantly less effective. Now let's move on to Liriano's actual results with a year-to-year comparison of his ERA, Expected Fielding Independent Pitching, strikeout rate, walk rate, and ground-ball percentage:

YEAR      ERA     xFIP     SO/9     BB/9      GB%
2006     2.16     2.35     10.7      2.4     55.3
2010     2.90     2.95      9.7      2.4     49.1

Those stats are all more or less what you'd expected based on the individual pitch changes. He's lost one strikeout per nine innings and has induced 11 percent fewer ground balls, which makes sense given the drops in velocity and slider ridiculousness. However, his walk rate has remained constant at 2.4 batters per nine innings, which can seemingly be linked to Liriano's improved fastball command canceling out the decline in raw, blow-it-past-everyone stuff.

What made Liriano so amazing in 2006 is that he combined an incredible number of strikeouts with tons of ground balls, which is the perfect recipe for a pitcher. Surgery has cost him about 10 percent of both his strikeouts and ground balls, but Liriano still ranks third in the league in strikeout rate and 12th in ground-ball rate. In terms of overall effectiveness, he's gone from a 2.16 ERA and 2.35 xFIP in 2006 to a 2.90 ERA and 2.95 xFIP this season.

Here's an even further breakdown of his results, based on strikes, swings, and contact:

YEAR     ZONE     SWNG     CONT     Z-SW     Z-CN     O-SW     O-CN
2006     54.8     47.8     65.4     64.5     76.0     27.5     35.3
2010     47.5     46.9     75.5     63.3     87.1     32.2     54.8

Liriano has actually thrown 13.3 percent fewer pitches in the strike zone (ZONE) this season, which perhaps could be chalked up to his no longer being able to simply overpower everyone with strikes. Opponents are swinging (SWNG) at basically the same number of pitches, hacking at 48 percent in 2006 and 47 percent this season, but they're making contact (CONT) on those swings 15.4 percent more often this year.

On pitches inside the zone opponents are swinging (Z-SW) at the same rate as 2006, but are making 15 percent more contact (Z-CN). On pitches outside the zone opponents are swinging (O-SW) 17 percent more often and also making 55 percent more contact (O-CN). I'm not smart enough to know for sure, but it seems like the slider going from ridiculous to merely excellent and the changeup going from excellent to bad could explain the swing and contact changes.

Add it all up and Liriano clearly isn't the same pitcher he was before elbow surgery. His velocity is down, his slider and changeup aren't as good, he's getting 10 percent fewer strikeouts and ground balls, and hitters are having a much easier time making contact against him on pitches in and out of the strike zone. He's also relying less on his slider and more on his fastball, likely due in part to the injury risk of the slider and in part to his improved command of the fastball.

It seems clear that the phenom who toyed with the league in 2006 is simply gone forever, but the good news is that Liriano was so spectacularly awesome then that even this post-surgery version with obvious declines in numerous areas is one of the elite pitchers in all of baseball. His combination of strikeouts and ground balls still ranks among the best in the league and his raw stuff is still capable of overpowering hitters, as the Braves saw first hand Friday.

Oh, and the other good news? F-Bomb 2.0 is still five months from his 27th birthday.