"Honestly," said A's general manager Billy Beane, "I'm worried he's going to be better. Seriously. And he's going to be up there an extra month. Yeah, I'm concerned he's going to be better, if that's possible."
Speed and defense don't go away. Not at that age. So Trout will have that at his disposal again in 2013 -- and the Angels expect him to get down to his normal weight by Opening Day.
But what can baseball fans expect after a season in which Trout batted .326 with a .399 on-base percentage, 30 homers, 83 RBIs, 49 steals and 129 runs scored, making him the only player to ever combine those numbers in one year?
The gaudy stats came in a year when not much was expected of Trout, who spent his first month in the Minors and only came up on April 28 because the offense was desperate. Now -- after gracing all the covers, appearing in Super Bowl commercials and becoming possibly the most-talked-about player in the game -- he has a big red target on his back.
But good friend Mark Trumbo believes Trout can handle that pressure "just a lot better than anybody I've seen."
"He's very easygoing," Trumbo said. "He's very competitive, but he's very easygoing.
"He's having fun," Angels general manager Jerry Dipoto added. "He's just out there having fun, playing the game, not too full of himself. He's ultra competitive. Ultra competitive. I don't think he has any fear in his DNA."
Noted statistician Bill James projects Trout to hit .325 with a .402 on-base percentage, 30 homers, 87 RBIs, 53 steals and 122 runs scored -- in short, he has him basically mirroring 2012.
There are several reasons to believe that. There's his speed, the kind that isn't prone to long slumps. There's his short, compact, simple stroke, which never requires much maintenance. There's the lineup behind him, with Albert Pujols and Josh Hamilton following two spots later. There's his ability to hit the ball the other way, or his comfort with two strikes.
And, as opposing managers saw, there's his ability to make quick adjustments.
"When he first came up, to me, he chased the slider a little bit, he chased a little bit out of the zone, and the second time, he was a different cat," Dodgers skipper Don Mattingly said. "Anybody who learns that quick will make the adjustments for whatever someone's trying to do to him."
"I have no doubt that Mike will very easily handle his transition from Year 2 to beyond," Dipoto added. "Like with any player, there will be adjustments, just like there were in Year 1 for him. He'll make them. He makes them day-to-day, inning-to-inning and month-to-month, and I don't necessarily think year-to-year is going to present an emotional challenge for him."
If Ron Washington is being nit-picky about Trout, he'll bring up his bunting ability. But the Rangers skipper also believes Trout can master that quickly under Mike Scioscia, and he can't find much reason to believe he won't keep hitting.
"He has that ability," Washington said. "And he seems to be a guy, from me seeing him, who wants to learn. So I don't think he'll ever take anything in this game for granted. And because he won't take anything in this game for granted, he has the ability to continue to play very well."
But the Majors can sometimes be a big cat-and-mouse game, all about adjusting and then adjusting to the adjustments. Trout tapered off a bit -- by his standards -- down the stretch last season, posting a .287/.383/.500 slash line after Aug. 1 and batting .257 in September. He also finished the year with 139 strikeouts.
Did the league figure him out?
Will Trout search more frequently for the home run, after hitting an uncharacteristic amount in his rookie season?
Can he fall victim to that dreaded sophomore slump?
"There's going to be some adjustments and there's going to be some ups and downs," Mariners manager Eric Wedge said. "There's no mistaking his talent and ability, but even the great ones have some ups and downs. He's less than a year into his career, so the league will make adjustments, and so will we."
That's when you start to get a gauge for Trout's mindset -- the one many of those around him will point to as the reason he isn't primed to crumble under the weight of expectations.
Trout seemingly doesn't feel the pressure to be great again. He appears oblivious to all the noise around him, about being the next Mickey Mantle or the new face of baseball or already the greatest player in the game.
When asked about the expectations heading into 2013, he immediately starts talking about the doubt.
"They can say what they want," Trout says. "I know what I'm capable of. I just want to go out there and do my thing. They take it out of proportion sometimes. 'Sophomore slump.' They're doubting me that I can't do anything better than that.
"I'm just going to go out there and have fun, do what I can to try to help my team win."