Celtics’ James Young working his way back up to speed

Young, the No. 17 pick in this year’s draft, has been recovering from a hamstring injury since making his debut in the preseason opener. Young scored 10 points in a 19-minute, 44-second stint in a 98-78 win over the Philadelphia 76ers Oct. 6.

“Today is as important as tomorrow for him, because he’s going up against Jeff Green or he’s going up against Avery Bradley or Marcus Thornton,” Stevens said before practice Tuesday. “Those are guys he needs to measure himself against right now.”

Young went full speed in non-contact drills during practice Monday, and Stevens said, “I was really impressed.”

Young, 19, has maximized his observation and study time, and now needs hands-on learning, Stevens said.

“I think we’ve got a pretty good idea how guys for the most part best learn, and he certainly is a guy who has picked things up very quickly,” Stevens said. “There’s varying degrees of what you can pick up off film, what you can pick up off the board.

“I’d much rather watch a film edit of 50 plays than look at 50 diagrams. But everything is better when you go through it: Show me how to do it, let me do it, let me teach somebody else to do it. That certainly applies [to Young].”

Young might be youthful but he does not seem to be in a hurry.

“I’m going to be careful what I do, and really go day by day,” he said. “I’m so young. I try not to move everything so fast, and just sit there, and when my time is right, my time is right. So try not to think about things too much and just wait.’’

Young said he is about “90 percent” recovered and felt no aftereffects from Monday’s workout.

“No soreness or anything, so that was really good,” he said.

Young is eager to get out of the film room and onto the court.

“Just get back into the flow of things, really,” he said. “Just act like I’ve been on the floor for a few games and try to go with everybody else. It helps a lot more than just watching video and stuff like that.”

The “younger guys,” including Dwight Powell, are expected to receive increased playing time against the Nets. Powell, 23, has totaled 40 minutes in five contests.

“You try to know the opponents as well as you can, but it comes down to how well you execute your stuff,” Stevens said. “So I don’t think there’s any reason to be into trickery or deception or anything like that.

“You’ve got to just be who you are. We’ve got to get better at who we are. And today will be that focus.

“We’ve gotten good minutes already from a conditioning standpoint, from a style of play, from trying different rotations. I feel like a lot of those questions are answered.

“Starters will have to be ready to play half the game or less, then play younger guys more than they have had a chance to play.”

Point guard Rajon Rondo (broken left hand) could be ready for the season opener against the Nets on Oct. 29, but he will not be rushed. “He won’t just jump in,” said Stevens. “He’ll only play when he’s ready to play well.” . . . The Celtics have waived Rodney McGruder, Erik Murphy, and Christian Watford and will waive Tim Frazier after Wednesday’s game. “We will keep Tim through tomorrow night because of potential minutes,” Stevens said. “I wish we didn’t have to waive them. They’ve been great teammates, they’ve put in extra work, they’ve come back in small groups and worked. A couple of them made mention they’ve gotten better, and that makes me feel good. They were all real professionals about it, you know. I will root for them, for sure.”