MLB.com's Jim Callis was among the first to report the news, and he provided contract details:
Moniak had been committed to UCLA before the draft, per MLB.com's Todd Zolecki. However, his deal with the Phillies ensures that he will forgo college baseball and work toward joining the big club as soon as next season.
Moniak took a pay cut of roughly $3 million, which Zolecki said will go toward signing some of the team's other prospects:
He is expected to start Friday with the club's Gulf Coast League team, per Philly.com's Matt Breen. The league consists of young draft picks and international players.
With no clear-cut favorite to go No. 1 overall in the draft, Philadelphia's amateur scouting director, Johnny Almaraz, believes the Phillies signed the best player available, per Zolecki.
I think you'll have a Gold Glove center fielder who will hit in the middle of the lineup and be a leader on the team.
He was No. 1 on my list -- he was the best player in the country. There was no projection with Mickey Moniak. He possesses the ability that a lot of college players don't possess. He can run. He can throw. He can hit. His abilities are superior, and that's why we took him.
Almaraz also said he expects Moniak to hit between 15 and 22 home runs a season.
These projections seem valid, as Moniak is a complete player who could develop into a stalwart at the top of the Phillies' batting order. MLB.com provided a profile of Moniak's skills:
Moniak will be a welcome addition to a Philadelphia team that has been putrid offensively.
The team ranks last in the National League in scoring this season after finishing with the third-fewest runs scored in 2015.
Philadelphia has a nice young core to build around moving forward. Outfielders Tyler Goeddel, 23, and Odubel Herrera, 24, are already significant contributors for the squad, with Herrera leading the team with a .302 batting average. Third baseman Maikel Franco, 23, leads the team in home runs with 11 and RBI with 33.
Add in Moniak and a couple of high picks in the next few seasons, and the Phillies could become a contender in the National League East in the near future.
Statistics are courtesy of ESPN.com.