Markelle Fultz, a one-year star at the University of Washington, is expected to be the No. 1 pick in Thursday’s draft – a pick that will now go to the Philadelphia 76ers as part of a trade agreed to Saturday.

The first report came late Saturday night, then came the confirmations. The official announcement is expected Monday. The Boston Celtics are trading the No. 1 overall pick in Thursday’s NBA draft to the 76ers for Philadelphia’s No. 3 overall pick, plus other compensation.

There will be more details to come. But know this: the Celtics are taking a giant leap of faith.

There is no other way to look at this deal, in which Celtics would also acquire a protected 2018 first-round pick from the Los Angeles Lakers or a 2019 first-round pick from the Sacramento Kings.

That’s a terrific draft haul in a normal situation, especially when combined with another unprotected pick coming Boston’s way next summer from the Brooklyn Nets as the final piece of the remarkable trade the two franchises made in 2013 that should ensure the Celtics two chances to crack the top three spots in the draft for a third straight season.

But the entire point of that deal with the Nets was to try to give the Celtics, then entering a rebuilding phase, a chance to draft a franchise-changing player. And, by most accounts, Fultz – the presumptive No. 1 pick – is precisely that kind of player.

That’s why making this move is such a huge risk on the part of Danny Ainge, the Celtics’ president of basketball operations.

Word has spread for weeks now that Boston is enamored with Kansas forward Josh Jackson, and by making this move, the Celtics could draft Jackson with the No. 3 pick while also adding another first-round pick in 2018 or 2019.

And while the Celtics aren’t alone in liking Jackson’s game – some even think, though it is a decidedly minority viewpoint, that he could rival Fultz and Lonzo Ball as the best prospect in this year’s draft – the heavy consensus is that Fultz, a 6-foot-4 guard is ahead of everyone in this class and destined to be a star.

For Philadelphia, the move is a no-brainer. Fultz is a perfect complement to the team’s two building blocks, Ben Simmons and Joel Embiid, and would give the Sixers a guard to go with their potential franchise cornerstone wing and big man. Fultz’s shooting ability would allow him to play next to Simmons, and he’s also going to be a strong shot creator in his own right. Assuming health – a big assumption, given that Simmons missed all last season because of a broken foot and Embiid has played 31 games in three seasons – Philadelphia looks like a rising powerhouse in the Eastern Conference.

The fact the Sixers are willing to give up either the Lakers’ No. 1 pick next year or the Kings’ pick the following year shows that General Manager Bryan Colangelo saw this move as one he had to make, and rightly so. This is exactly the kind of situation where a team that has collected assets like Philadelphia has should cash them in.

Boston clearly already has plenty going for it – the Celtics had the best record in the Eastern Conference this past season and should again be in the mix for the top seed in the East in 2017-18. And by possibly adding another top 10 pick for next year, the Celtics have even more assets to make a run at someone like Indiana Pacers star Paul George or, more likely, Chicago Bulls star Jimmy Butler, via trade next month after they attempt to sign someone like Utah Jazz forward Gordon Hayward or Los Angeles Clippers forward Blake Griffin in free agency.

Still, the Celtics may have had the franchise player they’ve been waiting for sitting right in front of them after winning the draft lottery last month. Fultz could be the kind of player Ainge and Co. have been waiting for ever since Draft Night in 2013, when the Nets handed over their drafts for the next half-decade for the aging trio of Paul Pierce, Kevin Garnett and Jason Terry.

By passing on Fultz, Boston may be resting its hopes both in the potential of Jackson, assuming they draft him, and the ability to procure even more game-changing talent this summer, as well as each of the next two years.

It’s a big risk. Time will tell if it was a wise one.