WALTHAM, Mass. -- There are nights when Isaiah Thomas returns to the Boston Celtics' practice facility to get up shots, and when he's finished, he takes a moment to look at the 17 title banners that ring the court and marvel at how he got here.

"Sometimes I'm in here alone, and I'm like, man, I play for the Boston Celtics. I'm the franchise player for the Boston Celtics. Like, it doesn't make sense," said the 5-foot-9 Thomas, the 60th and final pick in the 2011 draft.

"But at the end of the day, I dreamed about stuff like that. So even though nobody believed that, I believed that one day it was going to happen. For it to happen and for me to be living my dream, it's like every day I'm happy."

For the start of the season, Nike debuted campaigns for some of its top NBA players. There are posters around Boston that show Thomas driving at the rim with Chicago's Jimmy Butler trying to defend from behind with the headline, "Pick me last again."

It isn't lost on Thomas that a mere 20 months ago, he wasn't particularly happy. He was a third-string point guard tangled in the Phoenix Suns' backcourt spiderweb. Still, it came as a surprise when the team dealt him -- four months into a four-year contract -- to the Celtics in the frenetic final moments before the 2015 trade deadline.

Since that day, Thomas has spearheaded Boston's run to consecutive playoff appearances, earned his first All-Star nod, represented the Celtics on stage at the NBA draft lottery, served as the team's primary recruiter in the pursuit of top free agents including Kevin Durant and emerged as the face of one of the league's most storied franchises. With help from Thomas, the Celtics landed another All-Star this summer, Al Horford, and are the popular choice to push the Cleveland Cavaliers in the Eastern Conference.

Thomas beams with excitement when he talks about the potential for this year's squad. But after looking forward, he's presented with a curveball that takes him back: What if the Celtics had never traded for him?

"Where would I be? I don't know. Probably somewhere else," Thomas said. "I mean, the Phoenix thing just wasn't working out. It seemed like they didn't want me as bad as they did when the summertime happened. You never know. I don't know where I would be. I'd be somewhere."

Would Thomas be the face of another franchise?

"You never know. I mean, I always felt one day I was going to be, no matter where it was," he said. "I don't know. That's a tough question. I don't know where I would be. Knowing me, things would have worked out somewhere, but who says it would have worked out like it has since I got traded?"

As the conversation continues, Thomas is still processing the hypothetical. He eventually circles back to the question.

"I guess if that trade with me didn't happen, and this team never jelled -- everything just came together, slowly but surely, especially having a great coach in Brad Stevens -- if that all didn't happen, then Al Horford's not coming here. Kevin Durant's not considering us," Thomas said.

"And the world's not talking about the Boston Celtics as being a top-three seed in the Eastern Conference. That's just fact."

In his first full season in Boston, Isaiah Thomas put up a career-high 22.2 points per game en route to his first All-Star nod. Tim Bradbury/Getty Images

'It's like a 10 percent chance'

On Feb. 19, 2015, Thomas sat near the back of the Suns' bus that was set to take the team to the airport for a flight to Minnesota, where Phoenix was set to open the second half of the season. As the final minutes before the trade deadline ticked off, Thomas hoped the team would make a move to alleviate the backcourt logjam that was making everyone involved miserable.

Although Thomas was fairly certain the Suns were going to move publicly disgruntled Goran Dragic, Thomas still phoned his agent to check in as the clock ticked toward 3 p.m. ET. Despite his being just four months into a four-year, $27 million deal, Thomas knew there was a chance he could be moved too.

"My agent was like, 'There might be something, but it's like a 10 percent chance,'" Thomas said. "And he didn't even bring up Boston."

Back at the Celtics' practice facility, Ainge had resigned himself to the fact that there simply might not be a deal to be made -- enough so that Ainge phoned Stevens about 10 minutes before the trade deadline and told him the roster was likely going to stay intact. Across the country in Sacramento, Stevens told an assistant to get the players ready for the start of an afternoon practice at Sleep Train Arena.

Eight minutes later, Ainge called back. The Suns had re-engaged about a deal for Thomas that Ainge hadn't really considered a possibility because Phoenix had balked a few days earlier when Boston called to see if Thomas were available.

"I'm blessed, man. And I don't take it for granted because a year and a half ago, it was like, I was the third-string point guard. Years before that I was the 60th pick. A lot has changed and it's been nice."

On the Suns' bus, word arrived that Dragic had been dealt to the Miami Heat. Thomas recalls a sense of relief washing over the bus, as players were excited that the backcourt logjam might ease.

The deadline passed, but news about deals was still trickling out. Wright, who had been traded from Boston to Phoenix one month earlier, stood up and announced, "IT, you just got traded!" Thomas thought it was a joke. A Phoenix assistant coach climbed onto the bus a couple minutes later and confirmed the news.

All the Suns got in return for Thomas was veteran guard Marcus Thornton and a 2016 first-round pick (it was Cleveland's pick and checked in at No. 28 that year). Suns general manager Ryan McDonough, who cut his teeth in Boston's front office, later admitted, "If I could get a mulligan, that'd be it."

Gerald Green, who often shared the floor with Thomas in Phoenix during that 2014-15 season, said the two talked often about how they might thrive in the right situation. Green signed with Boston this summer, in large part because of Thomas' presence and the Celtics' status as contenders in the East. It doesn't surprise Green to see Thomas flourishing.

"We didn't want to see Isaiah go [in Phoenix]," Green said. "We were kind of blown away when he got traded because he was really one of the guys that kept the team pumping, on and off the court. So when he got traded, we kind of felt down as a team in Phoenix. We knew he was going to be successful here in Boston. We didn't know just how successful he could be.

"Just to see him to that point and this point now, I just smile, man. He was a guy that one team didn't want him, two teams didn't want him, and now a team like the Boston Celtics, who have championship aspirations, are just in love with him. It just makes me smile, man. It's kind of like looking at your little brother grow up."

'Isaiah was what we needed'

Stevens isn't one for hypotheticals, but presented with the question of where Boston would be without Thomas, he admits that Thomas' arrival was exactly what this team needed to move forward at that point.

"I've never really thought about [what might have happened without Thomas], but it made us different because we had a guy that -- and I've said this many times -- Isaiah was what we needed," Stevens said. "There's no question about that. And the players around him make him better too. I think he is such a good fit for the guys that are here, and they are such a good fit for him. And that's why it works, right? He's been great. It's fun having him around."

It's easy to forget now, but the Celtics' roster was in a constant state of flux during that 2014-15 campaign, in which Boston carried a staggering 40 different players. The roster overhaul really started in December, when the team traded Rajon Rondo, the last holdover from the 2008 title squad, to Dallas in exchange for a package that included Brandan Wright, Jameer Nelson, Jae Crowder and draft picks.

Crowder, used to playoff appearances in Dallas, remembers being leery of what Boston was trying to do, so much so that he confronted Stevens after a practice in January and demanded to know if the young coach was OK with tanking. Stevens was adamant that his lone focus was getting better, and the Celtics, a .500 team through mid-January, started making the sort of progress that calmed Crowder in the month leading up to February's trade deadline.

That progress also gave Celtics president of basketball operations Danny Ainge confidence to explore moves that had the potential to make the team better at a time when some wondered if Boston's rebuild would be better served by stripping talent and losing games.

"I think the biggest thing for us was, under most circumstances, [the Suns deal] would be a trade that we would do because of how we felt about Isaiah, all day long," Ainge said. "The only downside was we were going to get better in the second half of the year, when there wasn't much hope for us to really contend."

"That was the biggest question that, ultimately, it came down to. We just liked Isaiah better than a few spots higher in the draft, and we ended up making the playoffs that year, and I think that was good for lots of reasons -- just the morale of the team and our coaches.

"More than anything, we ended up getting a player that's hard to find in any draft, let alone going from -- what did we pick, 16 that year? If we had not done the deal, we probably would have ended up at maybe 12 or 13, I don't know. And we got Terry Rozier with that pick, who's going to help us this year."

With only one ball to go around in Phoenix, Isaiah Thomas was the odd-man out in the Suns' point guard logjam. Barry Gossage/NBAEGetty Images

'It's crazy to see Tom Brady's name on my phone'

Despite everything he has accomplished the past 20 months, Thomas is far from satisfied. He is enthralled by the success of others at the pinnacle of their sport. That's why he's close with boxer Floyd Mayweather Jr. That's why, in a summer filled with adventures, he ranks getting to meet Hall of Famer -- and childhood idol -- Allen Iverson as maybe his biggest thrill. Also, after they exchanged numbers at the Durant pitch in the Hamptons, Thomas now casually exchanges text messages with New England Patriots quarterback Tom Brady.

"It's crazy to see Tom Brady's name on my phone. It doesn't seem real. Just like playing for the Celtics and being that guy doesn't seem real," Thomas said. "Like meeting David Ortiz and him knowing who I am, all that stuff doesn't seem real. I'm blessed, man. And I don't take it for granted because a year and a half ago, it was like, I was the third-string point guard. Years before that, I was the 60th pick. A lot has changed, and it's been nice."

What hasn't changed is Thomas' desire to improve. Thomas averaged 22.2 points and 6.2 assists per game last season, and that barely tells the story of how important he was to Boston's offense. He's eager to prove to naysayers that he can maintain an All-Star level of play and continue to evolve his game. But what matters most to him is proving he's a winner, and his No. 1 goal is to take this team deeper in the playoffs.

"I just know the great players never get satisfied," he said. "I'm trying to put my name in the same categories as those players, whether it be Floyd Mayweather, Tom Brady. I'm trying to learn from them and use my platform to be able to reach out and have relationships with those great players because I want to see how they think.

"I don't know it all. I don't know how to win at a high level when it comes to winning playoff series. But I want to learn. I think that's the best thing about the great players: They want to learn, they are willing to learn, and they are willing to get better."

The Celtics starters endured some bumps early in training camp while integrating Horford -- mostly because everyone was being too unselfish -- but preseason play suggests the first unit should be one of Boston's strengths. Horford is such an ideal fit for this team, particularly the way he moves the ball offensively, and his back-line defense will help a team that tied for the fourth-best defensive rating in the league last season.

Even better, Horford's quiet demeanor allows Thomas to remain in the spotlight. Before preseason games at TD Garden, Thomas was announced last, with Horford coming out a spot before him during starting the lineup.

"Al's an easy guy to coexist with," Stevens said. "There's no question about that."

Thomas recognized that more talent was needed to get this team where it wanted to go. He would have been fine sacrificing some of his own spotlight if the team could have hooked Durant, and Thomas wants Ainge to keep swinging for the fences. Thomas knows that more talent helps make the game easier for him. He's thrilled to have Horford as his new running mate; it even allows Thomas to shoot for loftier goals, individually.

"I want more. I tell people: I want to be All-Star, I want to be All-NBA, one day I want to be an MVP," he said. "That's not just me talking. That's goals that I have. Being on the Boston Celtics and being able to win and make the playoffs, those are achievable."

Thomas, motivated highly by those who think his All-Star appearance last season was a fluke, has looked very much like a player hoping to get a return trip this February. Through Boston's first three games, Thomas is averaging a team-best 24.7 points per game while shooting 53.1 percent from the floor. Boston's offensive rating is 107.9 points per 100 possessions when Thomas is on the floor.

Thomas can become the third Celtics player in the past 50 years to average 24 or more points in Boston's first four games on Wednesday against the Bulls, and would join elite company in Paul Pierce and Larry Bird.

It's fair to wonder where Boston would be if that 2015 deadline had passed without activity. How would morale have been after another trip to the lottery? How would the Celtics have added talent without establishing a winning environment?

Where would the Celtics be without Thomas? It seems fair to say the future wouldn't look quite so bright.