The Inevitable Regression of Colby Rasmus

This has been a roller coaster ride of a baseball season. We're 133 games in, and, despite reaching a high of 14 games over .500 in June, and starting this month ten games over and in a playoff spot, it's now the end of August, the Jays have, for lack of a better term, completely shit the bed on their most promising season in decades. After watching that eleventh inning last night, it's at that point where I don't know how far back they are in the standings for my own personal sanity.

One thing this has kinda been mind boggling, intriguing and frustrating all at the same time: Watching Colby Rasmus and his puzzling, yet seemingly inevitable regression.

Last year, Rasmus slashed .276/.338/.501, posting a 129 wRC+, .365 wOBA, and a solid 11.2 UZR, all coming together for a career high 4.8 fWAR, in only 118 games played. He was a silver lining to probably the most disappointing season since 1987, considering the expectations. However, in the offseason, Blake Murphy of Fangraphs wrote a piece on whether Colby Rasmus could survive a trip from the regression monster. It turns out, he hasn't been able to.

You see, one of the most interesting and unpredictable aspects in baseball is dumb luck. If you've ever read Moneyball, you'd know that in the average baseball game, about one run is attributed to skill, while four others are attributed to luck. Over 162 games, this evens out for every team, and the skill shines through. Often, however, for one player, their luck evens out over the course of multiple seasons. Is that what we're seeing from Colby Rasmus?

Well, maybe not. This might be an average season from Colby Rasmus. Last season, Colby Rasmus had a BABIP (batting average on balls in play) of .356 (league average was .297), which was thirteenth highest among hitters with a minimum 450 plate appearances. In his vicinity, were the likes of Marlon Byrd, Miguel Cabrera, Jayson Werth, Matt Carpenter and Joey Votto. Despite Rasmus' insane batted ball luck, most guys who had the same luxury put up better overall offensive seasons.

2013 BABIP Leaders (Minimum: 450 PAs)

Rank	Player	PA	BABIP	wRAA	K%	oRAR
5	Jarrod Saltalamacchia	470	.372	12.9	29.5	10.1
6	Freddie Freeman	629	.371	36.2	19.2	33.6
7	Allen Craig	563	.368	21.9	17.8	15.6
8	Mike Napoli	578	.367	24.1	32.4	17.7
9	Starling Marte	566	.363	13.4	24.4	20.8
10	Joey Votto	726	.360	49.1	19.0	45.5
11	Matt Carpenter	717	.359	37.8	13.7	41.4
12	Jayson Werth	532	.358	37.0	19.0	35.8
13	Colby Rasmus	458	.356	18.4	29.5	16.1
14	Miguel Cabrera	652	.356	72.1	14.4	63.4
15	Marlon Byrd	579	.353	22.7	24.9	24.3
16	Andrew McCutchen	674	.353	41.7	15.0	47.0
17	Daniel Nava	536	.352	21.7	17.4	17.7
18	Brandon Belt	571	.351	22.8	21.9	25.6

Source: Fangraphs
oRAR=Offensive Runs Above Replacement, the offensive discriminant (in runs) used in fWAR

In that entire list of 13 guys, the only two guys with a worse oRAR than Rasmus are Jarrod Saltalamacchia and Allen Craig, and Mike Napoli is barely ahead. If you look at Napoli and Saltalamacchia next to Rasmus, they all have a major similarity: They strike out alot. The thing is with guys who strike out approximately 25%-33% of the time is, they need to have an inflated BABIP to have any sort of sustained success over multiple seasons. It's also worth noting that Rasmus was probably due for a regression last year as well, but two separate stints to the disabled list never gave him that chance.

So let's look at Colby Rasmus over the past two years, and see the difference.

Metric	Rasmus '13	MLB '13	Rasmus '14	MLB '14
BABIP	.356	.297	.286	.299
K%	29.5%	19.9%	31.5%	20.3%
LD%	22.0%	21.2%	23.1%	20.7%
LD Avg	.823	.690	.633	.693

While the BABIP is down this year, it's not sorely below league average. His line-drive% is still above average, and we've seen him line into the shift a few times. The big thing is his average on line drives. Last year, almost every line drive he hit fell in. This year, he's seen that regress almost 200 points. So, he's been a little bit unlucky, but not so much so that it's significantly affecting his production. In order for Colby Rasmus to produce more often, he needs to put the bat on the ball with some consistency. If you only put a ball in play two-thirds of the time, you need the kind of luck he had in 2013 to produce, and that hasn't happened in 2014, and the issue is compounded by the extreme shift used on him.

Now, let's take a quick glance at his defense. Last year, his UZR (the defensive metric in fWAR, measured in runs above/below average) was 11.2 runs above replacement. This year, it's down at -6.8 runs below replacement, which is a swing of 18 runs (almost two wins). If we use the extrapolated UZR/150, the difference jumps to 28.4 runs, which is almost three wins. The defense of Colby Rasmus continues to be a mystery; he's had two outstanding years (2009, 2013), three awful years (2010, 2011, 2014), and in 2012 he had a 0.4 UZR in over 1200 innings, which is average.

After a pair of Jekyll and Hyde seasons, where is Colby Rasmus' production headed in 2015? It's hard to say. This year has been a little unlucky, but it will be difficult to match the BABIP and line drive average that he had in 2013 in his career, considering the rate at which he strikes out.

But one thing is likely: with Anthony Gose having two of his three option years used up, Dalton Pompey's slingshot through the system, along with Jose Bautista and, touch wood, Melky Cabrera part of the future, whatever Colby does in 2015 probably won't be north of the border.


Note: All metrics are from FanGraphs, and are accurate as of August 26th.