(Short aside: I am a Cards fan and Rasmus was/is my favorite player, so I offer you this fanpost mostly as a masochist but also as a dowry to become a part of your community.)
There is no doubt that AA abided by the fantasy sports tenet to be on the side of the best player in a trade. But just how good is Colby Rasmus? Where does he stack up in the pantheon of Blue Jays outfielders? Is it possible that he could be the best patroller of turf north of the border since Major Mapleleaf?
First, let's take a look at who exactly should be considered as the best Jays outfielders of all time. I started with the list of all Jays OF since the franchise was founded, and summed their WAR for Jays service time. I also looked to see who had the highest WAR per season as a Jay. Then I inserted Rasmus where he would fall should he have played his entire career for the Jays. Results:
By cross-referencing this list, I came up with the 7 Greatest Jays Outfielders Evar (non-debatable). In no particular order: Jesse Barfield, Vernon Wells, Lloyd Moseby, Devon White, George Bell, Shannon Stewart, and some guy named Jose Bautista.
So, let's compare the career arcs of those 7 vs. Rasmus:
The graph is a little cluttered, but it is clear that Rasmus (in cardinal) had a better age 22 season than any 22-year-old Jays OF ever. While he progressed nicely in his age 23 season, he was outpaced by the huge spike in production from Lloyd Moseby, who had a sneaky good season - .315/.376/.499 in 1983 (134 OPS+).
Rasmus has taken a slight step back this year, and has been lapped by the field. Your guess is as good as mine as to why he has regressed this year as there is a broad variety of reasons and theories for his struggles.
Rasmus has a long way to go should he reach Best Jays OF status. Even if he steps up to 3-4 WAR per year, he'd need to bang out 7 or 8 of them in a Jays uniform to take over the career WAR title from Barfield. Even then, it wouldn't be an indisputable belt, as Devon White and Bautista have the edge in WAR per season. A closer look:
This graph puts in perspective some of the crazy seasons the Jays have enjoyed (even ex-Bautista). Jesse Barfield hit .289/.369/.536 in 1985 (141 OPS+) and followed it up with a league-leading 40 HR, .289/.368/.559 campaign. Devon White had three 5+ WAR seasons in a row from 1991-1993.
Clearly Rasmus has a long, long way to go to match those types of peaks. So obviously it is extremely premature to anoint him as the Greatest Jay OF Ever (and even Projected Greatest Jay OF Ever). But still shy of 25, the Jays have a promising young CF not yet in his prime years. I guess you knew that. Hopefully a change in bird color and habitat is all that he needs to get some wind beneath his wings. (Ew. Sorry.)
All statistical data (I used bWAR) taken from http://www.baseball-reference.com/ and compiled on my abacus. If anything is wrong, it's obviously their fault and not mine.