Celtics president Danny Ainge said Mickael Pietrus should be ready for game action by the middle of January after July knee surgery.

“It feels great [to be in Boston],’’ Pietrus said. “Since I have been in the NBA, my goal has always been to win a championship, and I have a chance to win one so I’m going to give it everything I’ve got with my new teammates. So hopefully at the end of the year, we get what we want.’’

Pietrus injured his right knee in March while playing for the Phoenix Suns. The Suns were close to trading him to the Raptors earlier this month, but Toronto called off the deal when Pietrus’s knee did not test at full strength.

Paul Pierce will play for the first time this season on Friday night against the Detroit Pistons in the 11-12 home opener for the Boston Celtics. He missed the team’s first three games, all losses, with a bruised right heel.

“Not a lot,” Doc Rivers said of the minutes Pierce will play. “We’ll just go with our eyes. He’s had just one practice and that was, what, three weeks ago?

“We will build him up each game.”

Rivers added that the Celtics could switch from their zone defense back to man if Pierce has trouble due to the lack of repetitions in practice/games because of his injury.

He added that the team’s 0-3 record had nothing to do with the decision to activate Pierce for Friday night’s game.

“Nah, we could be 3-0 and I’d be playing Paul tonight,” Rivers said.

Paul Pierce is impatient to make his season debut, possibly tonight for the Celtics’ home opener against Detroit.

“I’m close very very close,” he tweeted last night.

On Wednesday, Pierce admitted it’s been difficult to watch the start of the season from the bench.

“It’s tough, man, because I can see how my teammates need me,” he said before the Celts’ 97-78 loss to the Hornets. “But I think they’re doing all right out there in a lot of ways.”

Boston Celtics All-Star forward Kevin Garnett is about to become a small shareholder in the American-owned Roma football club.

Roma has confirmed that Garnett accepted an offer from James Pallotta, one of the four Boston executives that closed a deal in August to become the first foreign majority owners of a Serie A club.

Pallotta is also a minority owner of the Celtics.

Jeff Green intends to return stronger from surgery to repair an aortic aneurysm.

“I’m in a good place right now. I know the whole procedure, and I know when I come back I will be stronger than ever and be a lot better," Green said.

“And when the doctors give me the go, I’m going to take it to another level."

Green has been around the Celtics since his diagnosis and said it has been therapeutic.

“I’m very relieved, because I can play basketball again,’’ Green said before the Celtics lost to the Heat, 115-107, last night at American Airlines Arena. “It’s a blessing that it was found because you never know what could happen.’’

Under Doc Rivers, the Celtics have never finished any better than 15th in offensive rebounding.

Because the Celtics have been so consistently weak in this area, there has been a perception that this is something that Rivers doesn't stress. Not true, he says.

"We always wanted to do that," Rivers said. "That's been one of the most misunderstood things about us. We've always told our bigs, 'If you're under the basket and we shoot, how about going to get it?' "

Rajon Rondo had an outstanding 31 points, 13 assists and five steals (27.6 FIC40) in Boston's Opening Day loss to the Knicks.

"This is the Rondo we want," Doc Rivers said after the game. "This is what we talked about last year. Getting to the free-throw line. Taking the shots when they're open. I thought he was the aggressor in the game. I don't know if [he] can do that every night, but overall, that's the Rondo that we want. It was terrific."

"He attacked. He attacked early. He set the tone, got into the paint, softened up their defense," Ray Allen said. "It's a great sign for us."

"I was just trying to get us into transition," Rondo said. "Trying to get us to the line. Trying to get us some easy looks, get them in the penalty early. But it's only one game. When P [Pierce] gets back, obviously, some of the shots will go to P. Whatever the team needs, whatever Doc wants me to do, that's what I'll do."

Mickael Pietrus, who negotiated a buyout with the Phoenix Suns on Thursday, cleared waivers Saturday night and as expected, signed on with the Boston Celtics.

"His skills as a perimeter defender and an outside shooter provide great versatility to the roster," Celtics General Manager Danny Ainge said in a statement released by the Celtics.

The Celtics only have the veteran's minimum available.

That means the eight-year veteran would receive a pro-rated salary of about $1.2 million.

The Knicks have the highest average ticket price of the five Christmas Day games.

Here are the averages, according to information provided by TiqIQ.com:

Celtics @ Knicks: $516.09
Bulls @ Lakers: $466.02
Heat @ Mavs: $395.97
Magic @ Thunder: $295.71
Clippers @ Warriors: $104.95

Mickael Pietrus agreed to a buyout with the Suns and is now in the NBA’s two-day waiver period before deciding whether to accept Boston’s minimum contract offer.

“I think Mike likes the Celtics very much and likes that option very much,’’ said Pietrus’s agent, Bill McCandless. “I guess we’ll open up the present tomorrow at 6:30. There’s one team that was interested in trading for him and it did come down to the wire. I think there’s a 15 percent chance of a waiver claim.’’

Pietrus averaged 7.4 points in 38 games with the Suns last season after being traded from Orlando.