Predicting disaster: Should we have seen the collapse of Wells and Dunn?

Their were several really disappointing and disastrous seasons this year by players, but two of the more spectacular were Adam Dunn and Vernon Wells. I have already written about the disastrous Wells trade the Angels made, and so I won't elaborate on it here. I am more interested in whether, statistically, we could have predicted this to happen or at least explain why it happened. Wells had one big offensive season, that was in 2003 when he had a 6.1 O-WAR, .909 OPS, 1.61 PPG, .359 OBP, and 2.51 PAPP. You may notice something, although those numbers are solid, they aren't great, they aren't Pujols, Berkman, or Hamilton numbers. He has had 2 other solid offensive seasons, a 4.4 O-WAR in '10, and 4.6 O-WAR in 2006, but really has been pretty unimpressive other than that. His career OBP is .323, which is way under the league average at that time. His OPS and Slugging is better than average, but not by a whole lot. So it isn't a crazy notion to suggest that Wells wasn't all that good of a hitter anyway. However, this year has been bad, even for him. A .249 OBP, 660 OPS, 1.22 PPG, and 3.31 PAPP were some of the embarrassing numbers Wells put up. So what was the source of the difference for Wells? Shockingly, this was not the lowest Slugging percentage he has ever had. His BABIP was horrible this year, .214, but has never been very good, .272, .279, .262, .296 in the past 4 years. This year's runs created was the worst ever in his full seasons. His home runs and rbis per at-bat metrics are almost identical from 2010 and 2011. His groundball to flyball ratio is still about the same, but his line drive percentage is lower, but their was no gradual change, it was only this year. He is also striking out more, and walking less, and along with the low BABIP, that is a horrible combo. At least in all the metrics I am seeing, we can see why Wells is having a terrible season, and that he was overrated in the first place, but we can't say with any kind of confidence that we could have "saw it coming". Now on to Adam Dunn. He, unlike Wells, has always had good OBP, a .374 career, and .400 in his first full year in 2002. However, in 2010 with the Nationals it dropped to .358, which is not bad, but a decent drop from his career normal. In 2011, it dropped to a stunning .292. He has had 5 years of .900+ OPS, but in 2011, it was a terrible .569, with career lows in both slugging and OBP. There was absolutely no indication that the slugging would just go away. The Total Bases was also a mystery, he had at least 230 TB every year since 2004, but only had 115 in '11. Before his disastrous -2.3 O-WAR 2011, he had a 4.1 O-WAR in 2009 and 3.8 O-WAR in 2010. His secondary average, an alternative sabermetric batting average, had been over .500 over 5 times, but in '11, it was .296. Metric after Metric shows that Dunn was good until 2011. Whether looking at PPG, PAPP, BABIP, or RC, the story is the same. The only real thing that stands out in 2010 was how his Strikeout to Walk ratio got much worse. This carried over to 2011. But that is all we have to go by, a drop in OBP (still having a pretty good one in 2010) and strikeout to walk ratio. He did have a career low in pitches per plate appearance in 2010, but it was still very good (4.11), and in '11, he had a career high. The only thing I think we can learn from Wells and Dunn is that watching OBP is of the utmost importance, and that tying up lots of capital or trading away multiple players for one high paid one at the beginning of a season is unwise. If a player is making very little and stinks, then it doesn't hurt you as long as he is not on the field. If he is making tons of money (these two making $35 million combined last season), then it can cripple your team because you are unable to sign or trade for a replacement.