Michigan tried to double-team him and then tried a zone to attempt to neutralize him.

But when Purdue senior forward JaJuan Johnson takes a step back instead of driving to the basket, he is almost unstoppable. Once the Boilermakers recognized it in their 80-57 pasting of the Michigan basketball team on Tuesday afternoon, everything else opened up.

With Johnson a threat from all over, it opened up the lane for Purdue’s point guards. It opened up Purdue guards E’Twaun Moore and Ryne Smith on the 3-point line.

And when they starting making shots, as they did during a critical 17-5 run in the second half that blew open the game, it created more room for Johnson.

Even he admits that when he steps out to take a short, feathery jumpshot, he is a tough matchup.

“I get in a good rhythm anytime I hit those shots and I realize it’s tough for people to guard me when I hit those shots,” Johnson said. “They can’t just key on me inside or just outside. I can play off of whichever one is working.”

After a first half where Michigan held Johnson to 10 points on 2-of-10 shooting, he ended up being a major factor in the second half, finishing with 22 points, including making all 10 of his free throws.

His play — along with Purdue’s 6-of-7 3-point shooting in the second half — was critical for the Boilermakers’ success.

“His ability to shoot the ball set him apart,” Michigan junior guard Zack Novak said. “He’s so long, he can get his shot up over almost anybody. If he’s knocking them down, it’s just tough to defend.”

Stu Douglass starts With point guard Darius Morris pulled out of the starting lineup due to a violation of “core values,” it opened up the opportunity for sixth man Stu Douglass to start his first game since the end of last season.

“It’s a little different,” Douglass said. “Your mindset is a little different. Coming out, I just tried to attack it the same way, tried to bring the same energy but we just didn’t have it the first four or five minutes.”

Douglass said he found out Monday he’d be starting instead of Morris. He responded with carrying Michigan through the first half. He had 13 of his 15 points before halftime.

Michigan coach John Beilein, though, said Morris’ bench trip would last just one game and that Morris will start against Penn State. This likely means Douglass will go back to his sixth-man role.

Purdue had lineup changes of its own, starting D.J. Byrd instead of Kelsey Barlow.

“After watching them play Oakland, they kind of brought the kitchen sink against Keith Benson,” Purdue coach Matt Painter said. “We just wanted a little bit more skill in there to start, a little bit more balance.”

This and that Michigan had its first foul out of the year when Evan Smotrycz picked up his fifth foul with 4:38 left. … Michigan had its first announced sellout of the season. … Jordan Dumars was eligible for the first time Tuesday and dressed, but did not play. … For the second straight year, Michigan had its best player disciplined before Purdue. Last year, guard Manny Harris was suspended for the Purdue game following an “unsportsmanlike conduct in practice.” … Penn State coach Ed DeChellis told AnnArbor.com on Tuesday that freshman guard Taran Buie, who was suspended indefinitely for a violation of team rules Monday, will not play against Michigan on Sunday.

Michael Rothstein covers University of Michigan basketball for AnnArbor.com. He can be reached at (734) 623-2558, by e-mail at michaelrothstein@annarbor.com or follow along on Twitter @mikerothstein