Why The Cardinals Can’t Trade Colby Rasmus

…even if they want to.

Does anyone recognize this player?

Centerfielder.
Former top prospect, ranked as one of the top 5 in baseball at one time.
Great plate discipline (11% walk rate), but strikes out at a high rate (20+%).
Batting average hovers around .250.
Above-average power, posting around a .160 to .180 ISO.
Called out in the past for “attitude” issues.

Oh, you were thinking of Colby Rasmus? Sorry, I was describing B.J. Upton.

Colby Rasmus is an alluring player. In 2009, he was rated by Baseball America as the third best prospect in all of baseball, sandwiched between current stars David Price (#2) and Tommy Hanson (#4). That’s what happens when you’re a center fielder and you hit 29 homeruns in Double-A; everyone goes bananas about your potential.

But since then, Rasmus has generally failed to live up to expectations. Don’t get me wrong, he’s still been a great player — it’s not every day that a 22-year-old hits 16 homeruns and posts a 2.8 WAR season as a rookie. Rasmus followed that up with a spectacular year last season, hitting 23 homeruns and posting a .366 wOBA, before slumping back down to a .327 wOBA so far in 2011. He’s still an above-average center fielder and is on pace for just under a 3 WAR season, but Rasmus has yet to develop into the All-Star talent so many people expected.

Again, sound familiar?

As Dave Cameron pointed out in the trade value post yesterday, that’s the real problem with Rasmus: potential vs. production. Rasmus now has over 1400 plate appearances in the majors, and his skill set is becoming increasingly clear. He’ll walk around 10% of the time, strike out around 20% of the time, and steal a handful of bases each season. Unless he posts an extraordinarily high BABIP (like last season’s .354 BABIP), his batting average will fall around .250. Power is still his strength, and it’s possible that he could match last season’s 23 homeruns and .222 ISO again, but it’s looking more and more like he’s a 17 homeruns per season guy rather than 25.

Does Rasmus still have potential? Of course. Is he still valuable, even as just a 3.0 WAR centerfielder? For sure. But my point is this: it will be difficult for the Cardinals to get a fair return for him, as there is so much uncertainty about his peak value. The Cardinals are going to want to get a return back for him that factors in Rasmus’s potential, while other teams are going to be hesitant to pay that much for a player that is looking more and more like he may never reach that potential. Unless the Cards are willing to sell low on Rasmus, they’re likely stuck with him.

There are so many different comparisons you can make with Rasmus. Over the last year, he’s posted a .332 wOBA — very, very similar to Hideki Matsui, Coco Crisp, and Johnny Damon. Over his career, his offense has been 9% above average; Brett Gardner has been 7% above average and B.J. Upton has been 8%. He’s still only 24-years-old and could break out at any time, but at the same time, there have been many top prospects that have never reached the ceiling expected of them.

So how much patience do the Cardinals have? How likely do they think it is that Rasmus will reach his ceiling? It’d be a bad idea for them to sell low of Rasmus right now, but it’d also be a poor idea for another team to offer a package for Rasmus based on his potential. As much as Rasmus may frustrate the Cards, odds are they’re stuck with him for now.