Scott Bordow of the Arizona Republic noted McDonough called it an "overwhelming likelihood" the Suns stay at No. 1 rather than trading the top selection.
Phoenix finished the regular season with the NBA's worst record at 21-61 and won the draft lottery last week to obtain the first pick.
If the Suns keep the choice, they will choose from a prospect group headlined by Arizona center Deandre Ayton, Real Madrid guard Luka Doncic and Duke power forward Marvin Bagley.
In March, Ayton told CBS Sports Radio (via SB Nation's The Bright Side) he envisioned himself playing alongside Devin Booker with the Suns.
"Honestly, I could see myself in Phoenix," he said. "I could see a little Shaq and Kobe 2.0."
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Booker has emerged as a legitimate franchise cornerstone after averaging 24.9 points during the 2017-18 season, which would have ranked eighth in the NBA if he had enough playing time to qualify.
It takes two or three star-level players in order to contend, though. Ayton has the potential to become that second crucial building block for Phoenix after a standout freshman campaign with the Wildcats.
He was named Pac-12 Player of the Year after averaging 20.1 points, 11.6 rebounds and 1.9 blocks while shooting 63.5 percent across 35 appearances.
Although it's unclear whether the Suns prefer Ayton or one of the class' other top prospects, it sounds like they plan to keep the No. 1 pick when the draft takes place June 21 at the Barclays Center in New York City.