JaJuan Johnson answers call

BOSTON -- Maybe if it was the first time in JaJuan Johnson's basketball career that a coach had screamed at him, it would have been more remarkable. Heck, the Boston Celtics veterans and assistant coaches nearby seemed more startled by coach Doc Rivers' sideline outburst Friday night in Toronto than Johnson, who simply took his medicine and trudged back onto the floor.

"I wouldn't expect it any other way," shrugged Johnson, whose soft voice seems as though it could never reach the volume Rivers displayed that night.

"Throughout my whole basketball career, I've always had a coach that was tough on me," Johnson said. "I like it. It does nothing but motivate me. I know some people, when they get yelled at or things like that, they kind of get down. It makes me focus a little bit more, just get locked in. I have no problem with a coach yelling at me or telling me different things. It does nothing but help."

Here's what appeared to go down: Late in the first quarter of a listless loss in Toronto, an offensive play broke down as Johnson seemed unsure of his duties (he seemed conflicted between setting a screen and popping out). Rivers called a timeout to talk things over, only to have a similar play break down again.

When it did, Rivers called another timeout and, displaying rage not seen often in his eight seasons on the Boston bench, emphatically dressed down his players for a lack of execution, with Johnson earning his fair share of the venom.

"Two guys knew the play, one guy didn't -- and just one guy didn't," Rivers said after the game, not naming any names. "And it drains energy. Not being a professional drains energy. Being a professional is knowing every set you run, knowing your rotations, because it's draining for the pros who know [and] who do the work."

With center Jermaine O'Neal (knee, shoulder) and reserve big man Brandon Bass (knee) sidelined Sunday, Johnson seemed in line for a bump in playing time. But when Rivers was asked before the game if the 27th overall pick in last year's draft was ready for rotation minutes, he again didn't mince words about Johnson's play.

"Not yet," Rivers said. "I think he's getting close. You've got to execute when you're on the floor. That's an area he has to improve on. He's talented, but there's a level to me of intensity that you have to play with every night, and focus, and he's inconsistent in that. But he's getting there. He's a great kid and he will be there."

But Rivers went to Johnson early Sunday against the Chicago Bulls. A couple of quick fouls and some initial defensive struggles didn't set Johnson off on the right foot, but Rivers had little choice but to keep him on the floor.

Johnson responded by playing a career-high 33 minutes, chipping in 12 points, 4 rebounds and 2 steals while aiding size-depleted Boston in a 95-91 triumph at TD Garden.

Johnson clearly wasn't thrown off by Rivers' on-court admonishment.

"It just reminded me of my college career, just [Purdue coach Matt Painter] yelling at me," Johnson said with a chuckle. "I needed to be burned. We weren't doing what we were supposed to do. You don't want a coach to just sit back and let it happen. It was a good thing. It got everybody's attention."

Rivers has been highly complimentary of Johnson's work ethic over his first two months as a pro, often noting how both former Boilermakers (Johnson and second-round pick E'Twaun Moore) come to work each day and don't complain about playing time while trying to carve out their roles on a veteran team.

Injuries up front have started opening doors for Johnson. In a week's span, he logged 65 of his 103 minutes this season, and he has reached double digits in scoring in three of five appearances during the month of February.

Even so, Rivers clearly expects more out of the rookie and is pushing him to take his game to the next level.

"I take it as he wants me to give it my all, all the time," Johnson said. "Just getting out of my comfort zone and taking it to another level. I'm working toward that."

When a reporter asked if it was nice to see Johnson bounce back the way he did on Sunday, Rivers offered more tough love.

"Yeah, but he's got to keep doing it," Rivers said. "One game doesn't make a star. One season doesn't make a star. So you've just got to keep doing it, and he's got to do it consistently.

"He will, like I keep saying, he's a great kid and he wants to do it. He's young and he's still learning focus and all that. But he's a good player."

And even if Rivers wouldn't admit it, how the 22-year-old bounced back from a public flogging shows a lot about his character.

Rivers' words after Friday's game were a not-so-subtle reminder of why it's so hard for rookies to get off his bench. Rivers and his veteran ballclub demand a complete knowledge of the playbook and sustained intensity on the floor. Neither is easy for a first-year player, particularly one whose playing time typically comes in bite-sized chunks at the end of lopsided games.

With Bass sidelined for up to two weeks (and given Celtics' injury estimations, that should be taken with a grain of salt), it appears Johnson will get more opportunities to learn from in-game experience.

He's going to make mistakes, and Rivers might get upset. But we won't be surprised if Johnson responds positively to those negative situations.

Chris Forsberg covers the Celtics for ESPNBoston.com.