At the beginning of last year, we took some heat for leaving Adrian Gonzalez near the top of the first base rankings. Our reasoning, if I can speak for the consensus ranking crew, was that power takes the longest to stabilize and we didn’t know for sure whether or not the power was going to come back. The player himself said his shoulder didn’t hurt any more. As the season progressed, the truth became more obvious, and he dropped in the rankings.

Going into this season, we had three consecutive half-seasons of evidence that his power was gone. We dropped him in the rankings, and I even made a bet that the other former Padre first baseman — Anthony Rizzo — would outperform him this year. Now the player himself has admitted what we’ve known for a while and suspected for even longer.

Talking to Bill Shaikin, Adrian Gonzalez admitted that he’s had to change his swing since his shoulder injury: “I can still hit home runs,” Gonzalez said. “That is not going to be an issue. The full power is not the same.” And also: “Last year, I tried to go back to the swing I had before I got hurt,” he said. “I tried it for the whole first half, with horrible results.” And lastly, and perhaps most importantly for fantasy players:

Gonzalez said he figures to lose about five to 10 home runs per season. “I was a .280 hitter,” he said. “Now I’m more of a .300 hitter.”

You can see it fairly easily in the batted ball distance charts. Watch what happens in the second half of 2011 (the third red grouping from the right). See how there’s a group of dots at the top that just goes away and never comes back:

So yeah, those power days are gone. If he was barely a 30-home run hitter, by his own estimation even, he’s now a 20-home-run hitter. He’s probably right about that estimation, too. Players with a .158-.172 isolated slugging percentage and a fly ball rate under 40% last year included: Coco Crisp, Shin-Soo Choo, Alex Gordon, Carlos Santana, Rickie Weeks, Chris Johnson, Hunter Pence and Justin Morneau. The over-under set by this group is pretty much exactly 20.

But Gonzalez is smart. Shaikin also wrote that Gonzalez told him that he is “most effective now with a flatter swing that generates more line drives, rather than an upward swing that produces more power.” Going to the Joey Votto school of hitting was a great idea for Gonzalez, who has always shown opposite-field power.

Last year, Gonzalez was 57th in opposite-field percentage among players with more than 200 balls in play. If you limit the list to those with above-average isolated power, though, Gonzalez jumps to 18th on the list. And the transition might be underway still. Last year, his opposite-field percentage was 28.8%, and this year he’s hit 30% of his balls to the opposite field.

Gonzales has a lifetime .324 BABIP, and with an opposite-field approach, he can probably get the most out of his skill set by leveling his swing and hitting for doubles. With this new approach, you’ll probably want to take the ‘under’ on his power projections, since he hasn’t pushed his isolated slugging percentage close to .200 since the end of 2011.

But you could also take the ‘over’ on his batting average projections. And a .300-hitting first baseman with 20 home runs and buckets of runs and RBI is still a top-ten first baseman and a useful outfielder. Is he top five? You’ll have to wait for the next installment of the consensus ranks to find out.