Isaiah Thomas’ rise from ‘The Pizza Guy’ to the leader of the Boston Celtics

In Sacramento, the fans cheered for Isaiah Thomas as an All-Star, declaring him a most valuable player candidate.

In Phoenix, Thomas’ image adorned a game-day Suns billboard downtown.

These are not scenes from Thomas’ playing time in those cities. They are what it looked like this year when Thomas returned to the cities whose franchises discarded him for next to nothing.

Thomas’ undeterred confidence was justified in Boston, where his vision of greatness proved to be no joke.

Sacramento and Phoenix remain in the NBA’s second- and third-longest playoff droughts while Thomas could win the NBA scoring title and Boston is in the No. 2 spot in the Eastern Conference.

With the Kings, Thomas was more popular with the fans than the franchise, which favored Tyreke Evans, Jimmer Fredette, Aaron Brooks, Greivis Vasquez and Darren Collison over him. Tabbed as “The Pizza Guy” in a series of Sacramento commercials, now he is a franchise guy with a 29.2-point scoring average that is seven points better than last season. He is setting career-high shooting percentages from the field (46.2), three-point line (38.3) and free-throw line (91.1).

“Nobody believed it, except probably my family and my friends,” said Thomas, who skipped Boston’s weekend road trip to Brooklyn and Philadelphia to heal a right knee bone bruise. “Nobody believed anything that I’ve always said until I showed them and I’ve been given the opportunity here in Boston to showcase what I can do and I’ve taken full advantage of it.”

With the Suns, Thomas was limited to 25.7 reserve minutes a game behind a backcourt of Eric Bledsoe and Goran Dragic. He wanted the ball from the time the three point guards ominously posed for a training camp photo with their six hands on one ball.

By February 2015, Thomas and Dragic were granted trades over their disgruntled roles. The Celtics got Thomas for an affordable contract (he will earn $6.6 million this season) and a cheap trade price. They gave up a late first-round pick and Marcus Thornton, evoking Suns-Celtics lopsided trade memories of Dennis Johnson for Rick Robey in 1983.

“I thank them with all my heart,” said Thomas, who did not recall being on a billboard during his time in Phoenix. “It’s like they gave me a Christmas gift.”

Thomas’ intense play gained him a starting role by his first full season in Boston.

“Boston is bigger and better than everything in the NBA,” Thomas said. “It’s something I’ve never seen before and I’m just embracing it.’

After being the last pick of the 2011 draft, Thomas’ openness about having All-Star expectations were never taken seriously. He was used to that after always being overlooked, literally — at 5 feet, 9 inches — the shortest player on every team.

Thomas’ drive was unabated with a shoulder chip that was implanted by a 5-foot-6 father. Keith Thomas frequently took his preteen son to play with adults at Fort Lewis, an Army base outside their hometown of Tacoma, Wash. Keith is an Inglewood native, whose Laker fandom prompted a bet loss that led to naming his son after Isiah Thomas, albeit with a Biblical spelling.

Thomas has 43 consecutive 20-point games, which broke John Havlicek’s 44-year-old franchise record.

“He just is a guy that constantly strives to improve,” Celtics Coach Brad Stevens said. “He wants to be better. He takes every slight as a chip on his shoulder but he also takes every success as a hunger to do more. … He has been exactly what we have needed. Those guys around him fit his style well, a bunch of skilled players. We needed a guy who could get in the paint and create for others.”

Thomas can get to the rim and draw contact while keeping the ball away with an outstretched arm. His shot comes off softly with a flick. He has the footwork and bravado of a boxer. By no coincidence, Floyd Mayweather Jr, is among his best friends and an off-season training partner.

Thomas is using the Celtics’ addition of Al Horford and improvement of teammates like Jae Crowder to put Boston on a 50-win pace for the first time in six years.

Thomas earned the team’s leadership with his play in the games, voice in a room and example off the court.

“I’ve always been a leader,” Thomas said. “These guys follow my lead.”

It also is his city at this time of year. He recently talked to Paul Pierce about experience of being an athlete in Boston. After the Patriots’ Super Bowl LI win, Tom Brady texted Thomas that it was his turn.

“Maybe if I win a championship one day, I could almost compare myself to him but his [in-city attention] is 100 times worse than me for sure,” Thomas said.

“I don’t put no ceiling on myself. I still have got a lot of room for improvement. I feel like I haven’t shown the world everything.”

sports@latimes.com