ORLANDO — Late in the Celtics ‘ 82-73 victory over the Nets  on the second day of the Orlando Summer League, JaJuan Johnson  found himself up in the air with nowhere to go but straight down. He landed hard — really hard — on his elbow — but after a brief second or two on the floor, the second-year forward popped back up and headed to the free throw line.
“I’m all right,” he said later. “It’s not the first time I fell, so it’s all good. Nothing a little ice won’t take care of. It’s part of the game. I’m fine.”
There’s a too-easy analogy to make here about Johnson getting up off the deck, but after a rookie season that was mostly spent on the sidelines, Johnson is trying to prove himself and carve out a role on a team that needs frontcourt help. With Kevin Garnett  and Brandon Bass  back, the Celtics are set for starters, but behind them they have rookies and unproven players, for now. There’s opportunity for someone to grab a meaningful role, and frankly, they need at least two of their young players to grab it.
Johnson saw less than 300 minutes of court time as a rookie — only three other first-rounders saw less, not counting a handful of European players who haven’t come overseas yet. There’s no way to gauge anything from those minutes, but he did show some serious athleticism and the Celtics have always known that he can score if given the opportunity. Now they want him to show he can defend and rebound.
“We know he can pick and pop and shoot the ball, we just want him to do other things outside of scoring,” C’s summer league coach Ty Lue said. “Doing the right coverages on defense, blocking shots, running the floor, getting rebounds, stuff like that. He can score the ball so we want to see him do other things.”
Johnson attempted only five shots in their opener on Monday and he was more aggressive from the outset in their second game, knocking down a pair of outside shots. But the Celtics need to know A) if he can hold up against bigger opponents and B) what his natural position truly is in the NBA.
Johnson is too sleight to handle the physical pounding inside, but he is skilled and there was talk last season of ultimately making him into a small forward, albeit a long three. For now, he’s more comfortable playing the four, but he’s had a hand in guarding multiple positions in Orlando, which will serve him well down the line.
“Maybe the four, I think, because I’ve had the most reps at the four,” Johnson said. “I’m starting to feel comfortable at all of them. I think this experience being able to guard these positions will help me when his season starts.”
JARED SULLINGER AND THE ART OF OFFENSIVE REBOUNDING
On his second day of summer league, Jared Sullinger found himself opposite a legitimate 7-footer in former Cornell product Jeff Foote. Things did not go as well as they did on Monday when Sullinger carried the Celtics with 14 second-half points. He made only one of his nine first half shots and found himself unable to work effectively on the block.
As much as his back issues, this is the real reason Sullinger drifted down the draft order. The concern is that he won’t be able to score effectively as he did at Ohio State. The Celtics believe that Sullinger will be able to figure it out and his basketball skills will trump his lack of athleticism. His final numbers: Eight points on 3-for-12 shooting weren’t especially encouraging, but his 12 rebounds, including four on the offensive glass were a nice reminder that among other attributes, he knows how to get the ball.
“You’ve got to know your niche,” Sullinger said. “You’ve got to know if they shoot on the left side, 75 percent of the time it’s coming off on the other side. You’ve just got to get yourself in position. It’s not about jumping, it’s just about getting in the perfect position to be ready to get the rebound.”
Sullinger prides himself on being able to read his teammates tendencies and reacting accordingly. Take Jonathan Gibson, a quicksilver guard from New Mexico State who redeemed himself with 17 points in 14 minutes.
“It only takes me a couple of times to know my shooters,” Sullinger said. “With Gib, sometimes his shot come off short. It takes me a couple of days.”
Or E’Twaun Moore , who Sullinger played against as a freshman in the Big 1o.
“E’Twaun is a little bit of both,” he said. “If he’s by himself, sometimes it’s short. Y’all can look out for that and when you find that out, you’re welcome.”
The Celtics will be saying thank you if he can translate that skill into NBA games because the worst offensive rebounding team in the league will take all the help they can get.
LOOSE BALL AND LONG SHOTS
Second-round pick Kris Joseph showed a nice all-around game with 11 points on nine shots and five rebounds. Joseph does many things well, but it remains to be seen if he can latch on to one skill that will help him carve out a career. Still, the Celtics need depth on the wing and for a rookie minimum contract he could provide more bang for considerably less buck.
Fab Melo is raw. There’s no getting around it. He went scoreless in 13 minutes, but he did grab five rebounds and provided another resounding shot block that reverberated around the gym. Melo had only two shots, but he took a 15-footer with confidence, so that’s something.
Gibson was the breakout star of the day, one game after a a disastrous 0-for-5 performance. He hit five of his seven shots, including three 3-pointers in five attempts and he led their comeback after a dreadful seven-point second quarter … Jamar Smith and Dionte Christmas also had strong games.
Ty Lue is undefeated as a coach and he joked about throwing his hat into the ring for the vacant Magic coaching job. In all seriousness, Lue has done a fine job getting his team ready to play and giving everyone an opportunity to play, no easy feat in summer league. He’s proving that he deserves a shot on someone’s bench as an assistant in the near future.