After compiling a 3.36 ERA last year, Brad Lidge was traded to the Philadelphia Phillies, where he has thrived, posting a 1.87 ERA this year. Is Lidge’s success a fluke, or is it the beginning of a trend?

It appears that much of Lidge’s success this year comes from a very low home run rate. In fact, many of his statistics are almost exactly the same as last year:
 
Year    IP       Ks    BBs    BABIP      
2007    67      88    30    0.288      
2008    67.3   89    34    0.287     

But, of course, Lidge had a 3.36 ERA last year and has a 1.87 ERA this year. So what accounts for the difference? Homer rate:
 
Year    HR/FB      
2007    14.7%      
2008    4.4%     

Lidge is giving up 10% fewer homers on his fly balls than he did last year. That’s a huge drop, and is especially surprising given the fact that Lidge now plays half of his games in the homer-friendly confines of Citizens Bank Park. Other than his homer rate, it would appear that Lidge is the exact same pitcher that he was last year.

But actually, that may not be the case. If we look deeper, we can see that Lidge has actually been very different this year, most notably in his pitch selection and velocity.

Here is Lidge’s fastball:
 
Year    Velocity    %Thrown      
2005    96.0    53.9%      
2006    95.7    56.3%      
2007    95.4    58.0%      
2008    94.3    43.5%     

And Lidge’s slider:
 
Year    Velocity    %Thrown      
2005    87.1    43.7%      
2006    87.3    42.8%      
2007    86.8    36.4%      
2008    85.1    56.0%     

Notice that Lidge’s velocity is down for both his fastball and slider this year. And note his pitch selection: he is throwing far more sliders this year, at the expense of his fastball.

Interestingly, Lidge is getting less horizontal movement on his slider this year than last year. This year, his slider is moving 1.32 inches horizontally, whereas last year it moved 2.94 inches.

Finally, while Lidge has the exact same strikeout rate as he did last year, he has experienced a large uptick in called strikes this year, but has induced fewer swinging strikes. Additionally, batters are swinging at his pitches far less often than before:
 
Year    Called strike %    Swinging strike %     Swing %      
2005            24%                          31%                     76%      
2006            23%                          28%                     77%      
2007            23%                          29%                     77%      
2008            30%                          26%                     70%    

Perhaps Lidge’s decision to throw more sliders has led to batters laying off more of his pitches than usual, as batters would much rather swing at Lidge’s fastball than his slider. Taking this one step further, perhaps Lidge is better able to locate his slider this year, because it is breaking less, horizontally, than it has in the past. In other words, perhaps batters are laying off of Lidge’s slider, and he’s dropping it in for a called strike.

It seems rather odd that Lidge has managed to post the exact same strikeout and walk numbers as last year, despite a noticeable decline in his velocity, a vastly different pitch selection, and different amounts of called and swinging strikes than the previous year. Often times, when a pitcher shows trends like this, I’m inclined to believe it could be the sign of him getting worse. However, in Lidge’s case this may not be so. Although his fastball and slider velocities are down, he is still throwing both very hard. And the fact that he has still maintained a high strikeout rate suggests that he is as dominant as ever, even with somewhat "diminished" stuff.

It will be interesting to see if Lidge’s improved command (as evidenced by his higher amount of called strikes) is a one-year fluke (after all, his control isn’t any better than previous years) or the beginning of a trend (perhaps he sacrificed velocity for command). No matter what happens, however, Lidge will not be able to sustain his 4.4% HR/FB rate going forward.