The 32-year-old McCaw had invoked a clause in his New Zealand Rugby Union contract to take a break from the sport and had not played a match since the All Blacks lost to England in front of 82,000 fans at Twickenham last December.
On Saturday, there were about 80,000 less fans in attendance as the openside flanker helped his local side Christchurch to a 22-5 victory over University in a regional club competition.
McCaw, who had used his break to travel, began training by himself in May before he returned to his Super Rugby side, the Canterbury Crusaders, but has yet to play a game for the seven-times champions, who are in the playoffs that begin next week.
He played the entire 80 minutes on Saturday and said afterwards that he had felt a "bit rusty".
"A bit tired after that run around but good to get that under the belt," McCaw told TVNZ after the game. "The first half I was a bit rusty but in the second half, I got the feel of the game but did run out of gas a bit."
McCaw has refused to state whether he would be available for the Crusaders in the playoffs, having previously said he wanted at least a three-month conditioning window before he could front up for Super Rugby or test matches.
"That's a good question isn't it," McCaw said when asked if he could step up to the intensity of Super Rugby within a week should Crusaders coach Todd Blackadder need him.
"If that is the case then I don't see it being a problem."
The Crusaders, who beat the Wellington Hurricanes 25-17 on Friday and will finish second in the New Zealand conference behind the Waikato Chiefs, play in the first round of playoffs next week.
The semi-finals are on the weekend of July 26/27 with the final on Aug. 3.
The All Blacks begin the defence of their Rugby Championship title against Australia in Sydney on Aug. 17. South Africa and Argentina are the other teams in the southern hemisphere tournament. (Reporting by Greg Stutchbury in Wellington; Editing by John O'Brien)