Quick brain tease — Now that Adrian Gonzalez has been traded to the Boston Red Sox, how does his prospective value in fantasy leagues compare to Miguel Cabrera, Joey Votto, and Mark Teixeira?

A week ago, Gonzalez would clearly be somewhat behind those players in the rankings. Now? It’s not so clear. And the ambiguousness could make a major impact on fantasy baseball, influencing not only Gonzalez’s stock, but also valuations on Troy Tulowitzki, Robinson Cano, and pretty much all superstars heading into the 2011 season.

But first, let’s take a quick look at Gonzo himself.

For the past several seasons, Gonzalez has been one of the most consistent players in baseball — a 30-plus HR slugger with the ability to hit for average and get on base. If he’s never ranked in the top 5 among 1B, it’s largely because of environmental context, playing in the most pitcher-friendly ballpark in the majors with teammates who struggle to get on base and knock him in. Despite the handicaps, Gonzalez has averaged around 100 RBI and 100 runs scored for the past four seasons.

During that time, Gonzalez has 90 homers in road games — more than anybody else in the game. Only Albert Pujols during that time had a better road OPS. 

Gonzalez is not just moving away from a pitcher-friendly ballpark; he’s moving to a home stadium that will be kind to his talents. According to Baseball-Reference, he’ll be moving away from a ballpark in Petco that depresses production by left-handers by 10% and moving to a ballpark in Fenway Park that boosts production by left-handers by 6%. The parks factor difference between the two stadiums was enough to cut his HR total by roughly six homers per season. Adjusting his batting average to the new environment also yields shockingly great results — his .298 average in San Diego would have translated to a .323 average in Boston.

Gonzalez will also be playing in a superior lineup in Boston. Last season, he led the NL with the highest batting average (.407) with runners in scoring position. One has got to figure that the move to Boston will boost his RBI totals. Dan Syzmborski, who runs ZiPS projections at Baseball Think Factory, recently credited Gonzalez with an extra 14 RBI in his forecast for the upcoming season, which may be a conservative assessment.

In sum, it’s easy to imagine, assuming good health, that Gonzalez could be good for 35-plus HR, 115 RBI (or more), and a .300-plus AVG. That certainly puts him in the same ballpark of value as Miguel Cabrera and Joey Votto.

Many people still prefer those latter two, but for what legitimate reasons? Gonzalez’s off-season shoulder surgery? The fact that he hasn’t yet shown he can handle Boston fans and media? Perhaps, but almost everyone around baseball thinks that Gonzalez is a hard worker who won’t fold under pressure, and he recently passed a physical that was a prerequisite to the transaction.

Regardless of where exactly he ranks, it’s clear there’s more depth at the top-end of the 1B pool, and basic economics state that more supply translates to falling prices.

Let’s take an example.

Pretend we’re in the middle of the first round and an owner has the choice between Votto and Tulowitzki. A week ago, the consensus would be for Votto. Now? Does a drafter choose Votto when his competition can take the roughly equal Gonzo a few picks later? Does choosing Votto make sense when other 1B like Teixeira and Ryan Howard may now be available in the 2nd round, as a result of being pushed down in the rankings? Tulo’s edge over other shortstops should be given more credit given the increased strength and depth at first base.

In other words, we’ve just seen a major shakeup in talent scarcity. And it’s not just at the 1B position either. 

The fact that Gonzalez will be manning 1B means that Kevin Youkilis will be playing 3B — which is a big boost to a position that’s been suffering in recent years. Now, all those considering Alex Rodriguez at the end of the 1st round will have to consider the possibility of getting Youkilis a couple of rounds later. We’ll speculate that someone like Robinson Cano may begin to look more appealing at the end of the 1st round with drafters seeing more options at 1B and 3B and looking to fill out the rest of their lineup first.

In short, the move by Adrian Gonzalez from San Diego to Boston is a big rock thrown into an unsettled pond. It’s going to take several months to really measure the impact of this move on fantasy baseball valuations heading into 2011.