McGrady sprained his shoulder against Sacramento on March 24, and wore padding to protect it for the rest of the season. He had surgery in May to clear loose tissue in his shoulder and knee. He said his knee is "probably 75-80 percent" healthy and will take another two months to fully heal.
McGrady said an MRI revealed the arthritis in his shoulder.
"That's something I've got to deal with again this season," said McGrady, who averaged 21.6 points last season and was selected third-team all-NBA. "My knee should be ready to go by opening night."
McGrady said the shoulder injury was not going to keep him out of practices or games, but added that, "it's going to bother me."
On Tuesday, the Rockets hold their first practice with Artest after picking him up in an August trade with Sacramento. Houston went 55-27 last season, but lost in the first round of the playoffs for the sixth straight year.
Artest adds versatility on both ends -- a lockdown defender who can match up with guards or forwards and a multidimensional scorer who should take some of the offensive burden off McGrady and Yao Ming.
Artest averaged 20.5 points, 5.8 rebounds and 3.5 assists last season, but he's still known as much for his unpredictable behavior as his basketball skills. He'll never shed the notoriety as the central figure in the November 2004 brawl with fans at The Palace of Auburn Hills and he feuded with Kings management this summer before the Rockets acquired him.
The 28-year-old Artest said Monday that he's matured, on and off the court, and will keep his emotions in check because of the golden opportunity in front of him.
"I'm grateful to be on a team that has a chance to win," he said. "It adds extra motivation, extra 'go-get-it.' I kind of thrive under those situations. I like when I have something to play for. This year, I really do have something to play for."
One of the main attractions in coming to Houston was reuniting with Rick Adelman, who coached Artest for one season in Sacramento. Artest said he's never known a player who didn't get along with Adelman or like his free-flowing offensive system.
Adelman wants to see Artest and McGrady play together, giving the Rockets scoring threats on the wings.
"He gives us a guy, similar to Tracy, in that he can post up smaller people, he can take people off the dribble," Adelman said. "Tracy is a great passer, Ron will be a good passer. That's going to be our main challenge, working those two guys together, and see where they fit with Yao on the floor, too."
McGrady had to handle more of the offensive load when Yao broke his left foot in late February. He's averaged more than 21 points for the last eight seasons, but is 0-7 in playoff series.
In Artest, he may have finally found the perfect offensive complement.
"I know I get criticized a lot for not leading my team out of the playoffs," McGrady said. "It's hard when you don't have those pieces that you need to elevate you to that next level. Now, I have that and we'll see what happens."
Artest can also step into the role Shane Battier played for the Rockets last season, defending the opposing team's top scorer. Artest said he was asked to score more for the Kings last season and that coach Reggie Theus told him to ease up on defense to conserve energy.
"I think I can play a little harder on defense now," he said. "I always wanted to guard the best player. Coach wouldn't let me guard the best player all the time, because I had to score also. This year, I can go all-out on defense. I haven't had that joy in a couple of years."
Artest said he will happily accept whatever role Adelman gives him. He added that the enthusiasm since the trade hasn't worn off.
"This team right here, this team can be unbelievable," he said. "It's been an all-time high and it's kind of stayed there. I'm still excited. I prepared this summer and that's given me enough confidence, knowing I've prepared to have a great season."