Johnson, 22, was the eighth overall pick in the 2015 draft.
"He's really excited to be here and this is, I think, exciting for us going forward as we move to all of us trying to achieve a dream of contending for a championship in the NBA", Ujiri, the team president, said in Toronto late Thursday night.
News of the deal broke just an hour before the trade deadline at 3:00 p.m.
"I've been in rumours so many times I don't even look at it", Valanciunas noted.
Miles, 31, is averaging 5.5 points and 1.7 rebounds this season. He is one of the best passing big men in the National Basketball Association and in the past couple of seasons became a major weapon behind the three-point arc.
It will be interesting to see just how much of an upgrade this deal is for the Raptors, but it was certainly worth a roll of the dice considering how little they had to give up for the veteran big man.
However, Gasol is averaging 15.7 points, 8.9 rebounds and 4.7 assists this season with his best asset being his elite passing skills, defensive ability, capable three-point shooting at 34.4 per cent. The Raptors (39-16) currently sit in second place in the Eastern Conference standings and are in win-now mode with no guarantee Kawhi Leonard re-signs this offseason.
The Grizzlies came into this season insisting they could be a playoff team. "The trade also provides us with an opportunity to continue to develop two promising young players while giving us future flexibility". Are the Raptors taking a big risk and will it be worth it? Plus, Valanciunas can opt out of his contract this summer. Or, perhaps, Gasol comes off the bench. "I've never asked for a trade".
The Raptors are doing all they can to get to the NBA Finals this season, but you already knew that.