After all, he was one of the best of his generation—of any generation, really. His pursuit of the near-mythical .400 mark during his MVP season of 1980 came up just 10 points short, and to this day remains one of the most spirited cracks at it since Ted Williams reached it in 1941.
But for Brett, stepping into the batter's box, peering back at a pitcher and then putting the right swing on the ball came naturally. He worked his tail off, of course, but when someone would ask him to explain his sweet swing, he would usually just shrug.
It was easier to do than say.
Well, now he's getting paid to say rather than do. He's three weeks into a monthlong experiment as the Kansas City Royals' hitting coach, and just like Williams and scores of other greats who have tried to become coaches, Brett is finding results maddeningly slow to show.
"I've seen results in batting practice. I want to see them in games," Brett said in an interview with The Associated Press. "I've seen some guys alter their swings a bit, their stances a little bit, and they've had a little success, which is good. Some guys are working on it and it looks good in BP but it hasn't carried over to a game yet.
"When it carries over to a game," he added, "we'll be OK."
The question that will soon face Brett is whether he'll be around to witness it.
The Hall of Fame third baseman turned down numerous opportunities to coach over the years, mostly because he didn't want to deal with the daily grind. But he also didn't know whether he'd be any good at it, a hard admission for someone who has always excelled in baseball.
So even when the Royals reassigned hitting coaches Jack Maloof and Andre David and came calling once more, Brett accepted the interim job with reservations. He told manager Ned Yost and general manager Dayton Moore he would give it a month and see how things were working out.
That month is quickly approaching an end and the results so far—at least in black-and-white terms—have been modest at best and a humbling disappointment at worst.
The Royals were hitting .261 when Brett put on the old No. 5. They were averaging four runs a game, and ranked near the bottom of the American League in just about every statistical category.
Since he took over, the team is batting just .247 and scoring about 3.7 runs per game.
Their walk rate has improved ever-so slightly, but their power numbers have declined. They're hitting fewer home runs and extra-base hits, which is hard to imagine given the lack of power they were already demonstrating during the early part of the season.
"As an offensive group, we haven't come together as a team," Yost acknowledged. "We're still trying to take on too much responsibility individually instead of just doing whatever it takes."
But that old adage that numbers never lie? Well, Yost believe they can.
In just about every relative statistic, the Royals have regressed under Brett, but there are plenty of reasons to explain it. It takes time for changes to take hold. Subtle tweaks to a swing and, more important, a mindset can sometimes take months to reflect in the numbers.
In some cases, players have simply reverted to their expected mean.
Alex Gordon was hitting .340 when Brett came aboard but is just .152 since, putting his season average of .288 closer to what he'd be expected to bat. Lorenzo Cain's average has slid from .282 to .262, more in line with what he hit last season.
But in players that Brett has worked most closely with, Eric Hosmer and Mike Moustakas among them, there's been profound improvement. Hosmer's average has climbed from .262 to .275, and he is starting to pull the ball more. Moustakas has nudged his average over.200 after hitting .187 prior to Brett's arrival, often crediting his new batting coach with the improvement.
Exactly what has Moustakas been told?
"Our little secret," he said.
"I'm learning," Brett explained. "I've never done this before. Done it with my kids until they got to high school—I was the assistant coach on all their teams. But teaching an 8-year-old to throw a baseball and hit a baseball? Pretty easy."
This is certainly not easy, and in many ways a predicament. If Brett was to fail, how could the Royals fire the face of their franchise? And to whom would they turn next?
Perhaps that's why Brett seems to be living and dying with every at-bat.
When he hung up the cleats after the 1993 season, Brett said he did it because winning and losing didn't mean as much anymore. He never got as high after wins and never got as low after a loss. He didn't want to be simply playing for a check, so he chose to retire.
"It's completely different now," he said. "Now I'm (angry) when we lose and I'm very excited when we win. I mean, I'm more nervous in the games now because the games mean a lot more than when I was watching them on TV."
There's been more wins than losses since Brett took over—the team was 21-29 at the time and is 14-9 since, though most of that can be attributed to some stingy pitching.
But Brett believes the Royals are on their way toward sustained success, something that hasn't happened for the franchise in decades—not since he was still manning the hot corner, and his scrappy team expected to be a contender every year.
"Every day we stepped on the field," Brett said, "we expected to win, and I think this organization the past five years of losing 90 games, they were hoping to win rather than expecting to win. I think when we start winning, we'll expect to win again."
When might that happen?
"How about tonight?" he said. "They win tonight, they'll expect to win tomorrow."