Manny Ramirez's last great season was 2008. Putting up a mammoth .432 wOBA and 168 wRC+, Manny was good for 6.2 wins. After joining the Dodgers, he essentially carried the team to the playoffs himself with a Barry Bonds-esque wOBA of .500 for the final 53 games.
Never has a player's decline been so clearly one-dimensional.
Last year, as we all know, Manny was still a productive hitter but nowhere near the force he was two years prior. A glance at the four factors was, for me at least, surprising. Manny put up very similar walk and strikeout rates, and his BABIP was roughly the same. The obvious culprit, then, is his power. His ISO fell precipitously from .270 to .162, his HR per 150 games was more than halved from 36 to 15, he hit fewer doubles and triples, and his HR/FB fell from 22.2% to 12.7%.
Many scouts have been whispering about Manny's declining bat speed. It's unclear, however, whether this is true, or whether Manny has even suffered a power decline, as Slugging% and HR/FB are two of the slowest to stabilize statistics. Looking at some of Manny's more fundamental scouting statistics might, however, allow for a clearer picture.
First consider how often Manny has been utterly owned by an opposing pitching fastball. If Manny's bat speed is indeed decreased, it would stand to reason that he would whiff more often on high speed pitches.
|2008 Whiff%||2010 Whiff%|
*Fewer than 50 pitches
This data is not very conclusive. Manny is whiffing less on fastballs of EVERY speed. This is obviously the opposite of what was predicted above. Given that Manny also swung less, it's probable that this is a result of more selective swinging than anything else. We can't, however, point to this as evidence of diminished bat speed.
Another logical place to look would be Manny's ability to make "good contact". I looked at the portion of swings that Manny was able to land in the field of play for each pitch type per swing. Although not ideal, looking at what portion of swings ended up actually being balls in play is a measure of effective contact, in that it eliminates weak foul balls and whiffs (although it still includes weak ground balls and soft fly balls).
|2008 BIP per Swing
||2010 BIP per Swing
This data suggests that Manny indeed had a harder time being productive with his swings, and so that he had less time to time them, as the ball landed in play less often against every pitch (except changeups).
In this situation, Hit F/X data would be absolutely fantastic. Unfortunately, it has yet to be publicly available. As a result, we can't clearly say whether or not Manny's bat is indeed hitting the ball less or more hard. Given that this suggests that he is hitting fastballs less well but still hitting changeups well, it seems as though Manny's bat speed is indeed declining. That being said, given the dubiousness of these measures as indicators of bat speed in general, it's hard to state that with a significant of confidence.