But Pujols is so locked in -- on every pitch, every at-bat and every second of every practice -- it seems he hardly even notices.
"I don't think about that," Pujols will say -- and if you watch him closely on a daily basis, you start believing him. "People can criticize all they want. I don't go by what others say. That never helps, so I just never get caught up in it. I try to do my job and try to do what I can. I never try to do what I can't. I don't put that kind of pressure on myself. In the end, all I can do is what I'm capable of to help this team and this organization."
Pujols may not sound like a player striving to stick it to the naysayers, but he certainly has looked like one.
He arrived to camp a week early, showed up daily at almost the crack of dawn, played often, made a bunch of road trips, worked tirelessly, put up big numbers and now looks a lot trimmer than he did at the end of the Cardinals' World Series run last year.
But this is Pujols every spring, it seems.
"I asked several players that played with him and they said he does that all the time," veteran outfielder Torii Hunter said. "He's just doing what he does, which is go hard every day. I don't think he has anything to prove. The guy's done it all. He's done what he's supposed to do and he got what he got. That's fine. You're jealous? Get your kid to play this game."
Pujols is by and large the greatest hitter on the planet, and has been for a good portion of an 11-year career that has seen him win three National League MVPs and be the only man ever to amass 10 straight seasons of at least a .300 batting average, 30 homers, 100 RBIs and 30 doubles.
Yes, over the last three years, there has been some slippage in overall production, with Pujols' OPS declining each season, and his 2011 numbers -- granted, a .299 batting average, 37 homers and 99 RBIs -- being his lowest yet.
And, sure, the back-loaded nature of his deal means the Angels will be paying the 32-year-old Pujols $28 million, $29 million and $30 million in his age 39, 40 and 41 seasons.
But all that matters right now, with Opening Day fast approaching, is that Pujols makes a club that has missed the playoffs in back-to-back seasons a championship contender.
"I know I've had good success, but I'm always thinking about having the best season I've ever had," said Pujols, the nine-time All-Star who sports a career 445 homers and 2,073 hits. "Those are things that I focus on. And it's not just for me, it's for the whole team. In the end, that's what you play for -- to be a champion. All that matters is how many rings you have when you retire."
The Angels' 10-game deficit in the American League West last season, manager Mike Scioscia will admit, was due in large part to an underperforming offense -- one that ranked 17th in the Majors in runs and OPS. Kendrys Morales' return to health helps, but it's Pujols' insertion into the No. 3 spot and first base that changes the dynamic -- because of what he can produce himself and because of how those around him can benefit.
Suddenly the Angels seem to have a legit offense. As good as the one in Texas? Maybe not. But good enough to support a premium pitching staff -- which is why ace Jered Weaver remembers exactly what his reaction was when he woke up to the news of Pujols joining his team.
"I couldn't help but run around in my underwear and go find my wife and give her a big hug," Weaver said.
"Everybody in that clubhouse is pretty confident," Scioscia added, "but it's one thing being confident and another thing having a deeper team that's going to be able to turn that confidence into some tangible wins, and I think we're a better team now. I think that's what [Pujols'] impact will be."
The state of the Angels franchise changed drastically on Dec. 4, when owner Arte Moreno committed more than $315 million on Pujols and frontline starting pitcher C.J. Wilson. Now, after four months of anticipation, it's almost time to see how that'll all translate onto the field.
For Pujols, Friday night's game against the Royals at Angel Stadium will mark his first Opening Day without a Cardinals jersey on.
How will that feel?
"Like any other Opening Day," he said, plainly. "I'm happy with where I'm at, and I'm just going try to do the best I can to help the team win that game. That's my only concentration."
Maybe he really is a machine.
Alden Gonzalez is a reporter for MLB.com. Read his columns and his blog, Gonzo and "The Show", and follow him on Twitter @Alden_Gonzalez. This story was not subject to the approval of Major League Baseball or its clubs.