Late Wednesday afternoon, the news broke that Upton had signed a five-year, $75.25 million deal with the Braves pending his passing a physical.
Rays fans had an up-and-down relationship with Upton, who could look like the best player in baseball on any given day, or struggle on another. In the end, Upton left Tampa Bay amid a love fest that took place in the team's final game of the 2012 season.
Upton hit a bloop single into left field in his last at-bat in a Rays uniform. Sensing the moment, Tampa Bay manager Joe Maddon pinch ran for Upton, allowing him to receive one final standing ovation from an appreciative crowd at Tropicana Field.
Once Upton reached the bench, the longtime Ray began to tear up.
"I tried to hold it as long as I could, but I just couldn't," said Upton afterward.
Upton noted that the Rays were "all I know" in explaining his outpouring of emotion in Game 162.
"Ten years with the team ... I don't know, a lot of guys don't get to do that, and I've had that opportunity to be around great people -- people who care about one another," Upton said. "If it has to happen, I'm definitely going to miss them."
Indeed, Upton grew up with the Rays after the "Devil Rays" selected him with the second overall pick of the 2002 First-Year Player Draft out of Greenbrier Christian Academy in Chesapeake, Va. He signed in September of that year and made his big league debut in 2004 as an infielder, but he struggled in 45 games.
Upton did not play in the Majors in 2005, but in '06, Maddon's first season as manager, Upton returned, playing third base in 50 games and continuing to struggle in the field.
Upton began the next season starting at second base, but halfway through the season, he was switched to center field, now his primary position, and he gradually gained the reputation of being one of the better center fielders in the game thanks to his athleticism, range and arm.
In 2008, Upton was part of the American League champion squad that changed the team's image along with Upton's.
"To go from worst to first and see this organization turn things around and become a winning ballclub," Upton cited as his favorite memory. "Going to the World Series and winning the American League East. ... I'd have to say that '08 season [was my favorite]."
Over the next four seasons, Upton was a part of two more postseason teams.
"I've spoken often this year about how much I think B.J. has matured as a baseball player," said Maddon after the Rays' final game of the season. "He's matured as a person, of course, but as a baseball player, our relationship, how it's worked in the dugout, watching him play the game, all that stuff that's going on there -- all that stuff has dramatically improved throughout the course of this season."
Ben Zobrist, who has played with Upton for the past seven years, thinks his best is yet to come.
"I think he's going to continue to just get better," said Zobrist in October. "There's no question seeing him this year that he's just got better."
Part of the fans' discord with Upton has been in relation to numerous cases of missing the cutoff man, throwing to the wrong base and getting picked off. Maddon said late in the 2012 season that most of that baggage can be seen only via a rear-view mirror.
"His game has matured, meaning I've seen him throw to the right base and not the wrong base more consistently this year," Maddon said. "I've seen him choose the right places to run and not the wrong places. Decision making on the bases themselves, I think he's made better decisions this year on the bases. I've seen this maturation of his game a little bit."
Upton also addressed his past toward the end of the season.
"It's just learning, man -- the learning process, like knowing when to run," Upton said. "I know when to make people think I'm running, so the guy in the box sees better pitches. I know what counts to run in. I know what the favorable pitchout counts are. I know guys' patterns, what [they are] going to do in certain counts and when it's best for me to steal bags.
"I think it's just a learning process. I used to just run because I could run and chances were I was going to be safe, and sometimes not the best situations to run. But I've kind of picked those situations out and picked my spots to run."
Upton's numbers paint a compelling portrait. By hitting his 100th career home run during the 2012 season, he became a part of an elite group of players who had accrued 100 home runs and 200 stolen bases before turning 28. The others on the list include Barry Bonds, Rickey Henderson, Bobby Bonds, Eric Davis, Cesar Cedeno, Hanley Ramirez and Lloyd Moseby.
Though Upton finished the season with just a .246 batting average, he had a career-high 28 homers, led the team in RBIs with 78 and swiped 31 bases.
"It happens pretty fast," Upton said of his time with Tampa Bay. "It seems like it was yesterday."
Maddon said on the final day of the season that what he would remember most about Upton was how much the 28-year-old had grown as both a player and a person.
"I really enjoyed our relationship a lot," Maddon said. "This year was truly the year I saw him blossom."
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.