But most of all, he needed them to believe in the possibility they could play as one fluid unit when the calendar flipped to October.
"The whole point was to just have it out there on a daily basis, so when someone's walking behind somebody, they can see it," Maddon said of the idea to emblazon the "9=8" slogan on T-shirts.
"We have little signs on the wall, again, reminding. I know a lot of times they will walk by and not focus on it, but sometimes, just for a moment, they will. And the impact of that moment is worth it. That's the way I see it."
It is the same precise line of thinking that gave way to the epiphany behind the mantra, during one of Maddon's frequent offseason bike rides.
The idea is nine players playing nine innings together to become one of the eight teams in the playoff hunt.
Crazy to anyone outside the Rays' clubhouse, the shirts boldly proclaim that a team that had finished out of last place only once in its 10-year history could have visions of October.
"It makes all the sense in the world," Carlos Pena said. "I mean the way we play baseball, it's exactly that. It's just [Nos.] 1-9, good defensive play, good baserunning. It's even sweeter because we have been that team in the past where we were only envisioning what we wanted to be. All of sudden, this is materializing, and it's so rewarding to see it come to be."
The Rays are currently a franchise-record 20 games over .500, a 3 1/2-game leader in the American League East race and, as of Thursday, the team with the best record in baseball.
Crazy, no more.
"Now it's real," J.P. Howell said. "I think Joe knows what he's doing. I mean you got to really trust him and the moves he makes. Everything about him, he does with his gut, and I trust people that do that."
But the real magic has been each player's ability to not only put faith in the man behind the T-shirts, but in each other.
"We are a team, that's the biggest thing out of this," Trever Miller said. "We are a cohesive unit and the epitome of what a team is, on and off the field. Guys love it when the other guy does well. There's none of that, 'Oh, I hope he fails so I can succeed.' And that goes a long way through the course of the season. Everybody has accepted their role, whatever that may be."
True to the total team effort has been the revolving door of unsung heroes.
"I think as much as it's 9=8, it's much more along the lines that 13=8," Gabe Gross said. "Because not only is it the nine guys on the field, but you got really good guys who are getting spot starts."
"It's just been amazing how it seems like each guy on this team has come up and contributed in a huge way at different points in the year. And that's really been the key to our success, having different guys step up at the right time at different times."
The resident walk-off king, Gross has been "that guy" in three of the Rays' recent wins; a piece that has welded perfectly into Maddon's master puzzle.
Gross wasn't there when the team was initially told about the T-shirts this spring, but the outfielder -- acquired in a trade from Milwaukee in mid-April -- understands their importance.
So does Grant Balfour, who was one of the Rays' final cuts in Spring Training, but has been a driving force in the bullpen since his recall May 29.
"I got mine when I came up," he said, of the T-shirts. "I saw everyone wearing them and said, 'Man I need to get one of those.'"
While the ever-meticulous Maddon has thought up another use -- to get nine more wins out of the defense -- he claims the fated day the shirts arrived wasn't part of his grand scheme.
"It was during the Red Sox series when we swept them [April 25-27] here," he said. "I would like to say it was calculated, but we were just waiting on them [to come in]. The coincidence was they came at the right time."
And if the Rays can keep pace with a torrid first half of the season, Maddon's math could reach dizzying heights.
"Joe should have a little side hobby," Miller joked, "selling these T-shirts."
For now, the payoff in the popular garb is in the numbers.
"They've all done well," Maddon said, following Tuesday night's series-clinching win over the Red Sox. "You can't single out one guy on this team as being the reason we're in the position we're in. It's a team in every sense of the word, and that's what I'm most pleased about."
And if the Rays have proved nothing else during one of the most stunning turnarounds in baseball history, it is that there are plenty of variables in their formula for success.