Comeback taking shape?

Now he stands as the 16th member of the Celtics - sort of like being the fifth Beatle - hoping for an opportunity to return to the league. Sweetney, always a player with weight issues, is well above his previous playing weight. At Media Day, he looked uncomfortable with the spotlight. Wearing uniform No. 45, he lumbered through the Celtics’ practice facility in Waltham, unhappily posing for pictures, then walked to the locker room when it was over.

There is still much work to do. Sweetney took the first step by signing a training camp contract with the Celtics, but the NBA is not so forgiving, especially when players eat their way out of the league or appear apathetic. Sweetney was guilty of both.

The ninth overall pick by the Knicks in 2003, the 6-foot-8-inch Sweetney played little as a rookie but was a solid contributor off the bench in 2004-05 under Isiah Thomas. But Thomas made the ill-fated Eddy Curry deal and Sweetney was shipped to Chicago, where he, not surprisingly, was not a Scott Skiles type of player.

After two seasons, the Bulls made no effort to bring him back, declining his fifth-year option. It was over for Sweetney, and his mind wasn’t focused on NBA success.

“First year, I just had some personal stuff going on in my family,’’ he said. “And the second year, I was pretty much down in Miami working out at FIU [Florida International University] trying to get myself together.

“I played basketball all my life and then I get to a situation where I wasn’t playing,’’ he said. “It was hard for me to get a gauge of the workout plan and doing all that other stuff not knowing. Obviously those two years of me not playing in New York, I never knew I was going to play, so I was, ‘OK, do I work out?’ I didn’t.’’

Sweetney had been a beast in his three years at Georgetown under coach Craig Esherick, averaging 22.8 points and 10.4 rebounds during his junior season. He was always a burly player, but he had enough athleticism to compensate for his size. Things changed once he reached the NBA, and the explanations for his downfall are scarce.

“I thought he had a great college career and I thought he would be a great pro,’’ said Esherick, now a professor at George Mason. “I have to be honest and tell you I am surprised he didn’t continue to be a heck of a player. He played very hard for me.’’

Esherick, like many others, lost contact with Sweetney in recent years. Sweetney barricaded himself in Miami and worked out with former Georgetown and NBA great Alonzo Mourning to regain a semblance of shape. His road to physical respectability is hardly finished.

Sweetney strained a hamstring during the Celtics’ summer league session in Orlando, and while he is effective when practicing, his lack of conditioning is apparent.

“He can play, but conditioning is always going to be a factor,’’ Celtics coach Doc Rivers said. “But Michael Sweetney’s an NBA player. There’s no doubt about it. He has great feel around the basket.

“By mid-practice, he takes a dip. The first half of practice, he looks really good, and then right when fatigue happens, he’s gone. And that’s expected.’’

Despite his sojourn, Sweetney doesn’t turn 27 until Oct. 25, and he has very little NBA mileage on his body. The Celtics would have to waive, trade, or release a player to make room for Sweetney on the roster. Considering the quality big men they have, and the value of rookie Lester Hudson, that would seem unlikely.

Sweetney may have to continue his comeback in the Development League. He said his personal problems are in the past, as is his questionable work ethic. He is silent during times when other players are exchanging barbs and jokes. He slips out of Salve Regina University when workouts are over. At a time when he thought he would be enjoying the fruits of a second lucrative NBA contract, Sweetney is just trying to prove he belongs.

“I think, right now, it’s more of me understanding [the NBA], and I just gotta get it back,’’ he said. “I want to prove to people, prove to myself that I can still play. I’m not washed up. I’m not old. I just want to play basketball again.

“I’m 26 years old. I say I got another 10 years if I keep my body right, keep myself ready mentally and physically. I’ll be OK.’’

Instructional league

The league is prohibiting players from using Twitter and Facebook during games, including halftime. It will allow the individual teams to police players on social networking at other times.

When he was with the Bucks last season, Charlie Villanueva posted to his Twitter page during halftime of a game. Villanueva and Toronto’s Chris Bosh even had a competition to see who would be first to 50,000 followers. Bosh won.

The league also warned teams about players standing up in the bench area during games. Many times in tight, late-game situations, players at the end of the bench stand to watch the action. They tend to block the view of fans, many of whom are season ticket-holders paying premium prices for seats. In some NBA locales, fans have yelled at players on opposing teams to sit down.

To appease these fans and reduce banter between players and premium seat-holders, the league has warned players about standing. Fines will be levied if they stand too long.

Finally, the league told players and coaches not to berate replacement officials, who began work with Thursday’s Utah-Denver preseason opener.

In 1995, players and coaches were highly critical of replacement officials, which served as a bargaining chip for striking officials. The NBA wants players to refrain from complaining about calls as they did 14 years ago.

Neither Utah coach Jerry Sloan nor Denver’s George Karl had any criticism about the replacement crew that worked Thursday’s game, which was won by Utah, 103-87.

The officials can’t be blamed for the teams missing a combined 35 free throws. How about a memo on that?

Etc.

Gary Washburn can be reached at gwashburn@globe.com.