The Mets were swept by the Phillies, shut out two games in a row, traded a personal favorite of mine in Ryan Church for Jeff Francoeur, and are now nine full games back. This is what greeted me upon my return from Bermuda. I don’t think I could have picked a better week to leave the country. While I was catching up on the sports world, I heard Keith Law on ESPN radio discuss the Roy Halladay situation. What was specifically interesting to me was that he stated (I’m paraphrasing) that when looking to see if a pitcher has entered his decline phase, he predominantly looks at fastball speed and home run rate. Law continued that once a pitcher loses his fastball, he rarely gets it back. The first pitcher to come to my head when I heard this was Oliver Perez.

Proponents of the Perez signing often cited his potential or upside with Oliver’s 2004 season being cited as Perez’s ceiling. The argument being, if Perez was good once, he might be able to do it again—which is kind of the reasoning for the Francoeur trade. The problem with this line of thinking is that Perez was a very different pitcher in 2004; mainly, he threw 95+ MPH. The—admittedly inconclusive—chart below compares Perez’s FIP with the average speed of his fastball according to FanGraphs.

The linear trend line is not statistically significant; however, I think the chart does have merit. I’m not saying a faster fastball yields a better pitcher; rather, a flyball, two-pitch, power pitcher probably needs a good fastball to remain above average. Thus, if Oliver needs his fastball to be worth his price tag, a declining fastball would be big trouble.

Crap. I went with a polynomial trend line just because my heart told me to, but trend line aside, Perez’s fastball has not been close to his 2004 level in five years. However, it should be noted that Ollie’s 2009 fastball average will probably go up, as he was pitching hurt for most of the sample. Nevertheless, this is very worrisome if Law is correct that pitchers never get their fastballs back. The other day, Eno Sarris wrote,

“The year-27 peak theory has been disproved for the most part. An oft-referenced study by Schulz et al, done in 1994 by surveying the statistics of over 388 players that were active in 1965, found that major league baseball players peak between 25 and 28 years old. The reason for the range is that their peak is usually determined by their age when they broke into the majors. It follows that you would peak later if you debuted later. But the law of the bell curve also applies, and the later you join the league, the earlier you leave the league for the most part.”

Thus, Perez could have simply peaked early and, as Law would probably state, begun his decline phase. It’s really not that unheard of that some players peak earlier in their career. The one silver lining comes with the second part of Law’s statement, that home run rate is another metric he likes to focus on regarding decline.

Ollie’s home run rate is relatively stable, which is a good sign, but, unlike fastball average, home run rate is greatly affected by park factors.

For comparisons sake, here are Johan Santana’s charts:

Fastball x FIP (The 91 MPH plot point is his 2002 100-inning season as a swing man):

Year x MPH:

Year x HR/9:

Santana’s three best FIP seasons have coincided with his top three highest fastball speed seasons. Unfortunately, Santana’s fastball has been declining since 2006, and his homerun rate is increasing; thus, he is in his decline phase. This isn’t a terrible thing, since he is declining from superhuman 7 WAR seasons, has been worth roughly 5 WAR the past two, and should be very good for years to come.

But in order to end on a high note, I still think Perez can gain some zip on his fastball; unlike Johan, Perez’s mechanics are terrible. As the first article linked above showed, Perez was throwing in the high 80s in 2006 because of poor mechanics rather than “losing” his fastball. Still, the 93 MPH average fastball pitcher is gone and never coming back but the serviceable 91 MPH, 4.50 FIP model should still be here waiting for Jonathan Niese to pass him on the depth chart.