BOSTON – During the Boston Celtics’ open practice on Tuesday, R.J. Hunter hit a sweet-looking 3-pointer, but his lithe frame had trouble at times getting through screens.

Jordan Mickey made a couple of sensational plays defensively, but had moments when he struggled to hold low-post position against his stronger, more seasoned teammates.

And while Terry Rozier hit some big shots in the open practice, he too had an occasional issue defensively.

In other words, the Celtics’ rookies were doing exactly what rookies tend to do the first few days of training camp.

“I’m still learning the pace of it, just trying to get better,” Rozier, the 16th overall pick in June’s NBA draft, told CSNNE.com. “I’ve had a lot of vets talking to me. So far it’s been fun.”

Celtics head coach Brad Stevens has no expectations for his first-year players other than focus on improving one play to the next.

“They’ve all had moments,” Stevens said. “And probably not as consistently as some of the guys that have been there, done that. But they have had some real moments. That’s just part of it.”

Mickey, a second round pick in last June’s draft who signed a four-year, $5 million deal this summer, says he’s feeling more and more comfortable with each passing day.

“It’s been a big learning experience for me,” Mickey told CSNNE.com. “Just trying to catch up on everything, stay focused; try to take everything in.”

Hunter echoed similar sentiments.

“There’s just a lot going on, and you have to try and pick up on as much as you can as quick as you can,” said Hunter, selected by Boston with the 28th overall pick in last June’s draft. “But this is what you worked so hard for, to be in the NBA.”

Because of Boston’s depth at just about every position, none of the team’s first-year players are being counted on to make a major impact this season. But that won’t affect the approach Stevens takes with his young players who have a relatively full plate on and off the court.

“They have a lot going on in their minds right now,” Stevens said. ‘You really throw a lot at them the first couple of days.”

Celtics guard Avery Bradley remembers those days all too well. In his sixth NBA season, the 25-year-old provides the kind of perspective on training camp that first year players like Rozier appreciate.

“He’s definitely in my ear, helping me out there,” Rozier said of Bradley. “Having good vets makes this all a little bit easier.”

Said Bradley, “Figuring out your pace and rhythm is probably the biggest challenge; at least it was for me and I see that guys who came here after me, it wasn’t easy for them either. It just takes time, that’s all.”

Isaiah Thomas said he was very impatient during his first training camp with the Sacramento Kings.

As the 60th and final pick of the 2011 NBA draft, Thomas felt fortunate just to be invited to training camp.

“I didn’t even know if I would make the team,” Thomas told CSNNE.com. “So I was doing more than expected. I mean like water breaks; I was sprinting to the water just to get noticed.”

Thomas says his advice to rookies is pretty consistent.

“You can control what you can control. Work hard, be a good teammate and do the little things,” Thomas said. “It’s not all about scoring or standing out in that aspect. It’s just about fitting in and at the same time standing out; showing you do belong here.”

The players and Celtics’ brass are confident about all three rookies having a place in the NBA.

For now, getting through training camp while leaving a favorable impression is the goal for all.

“It’s just getting to that point where you’re doing things unconsciously instead of thinking about everything,” Stevens said. “That takes a while. That’s not something that’s going to be solved in three days, three weeks, three months most of the time.”