The 35-year-old New Zealand defender played the full 90 minutes in QPR's 1-1 tie with West Ham United in east London. Nelsen, whose playing contact expires June 30, is in talks with the Premier League club about leaving early to take over his MLS coaching duties.
New president and GM Kevin Payne says the team has a "pretty good idea" when Nelsen will arrive. Assistant coach Fran O'Leary is in charge in his absence.
Toronto's first day of camp at its north Toronto training facility was not open to the media so local reporters had more success watching Nelsen, whose game was televised.
Toronto players took part in medicals and some physical testing.
French striker Eric Hassli, who reportedly wants out, was expected to arrive in town later Saturday and be at the training ground Sunday, the club tweeted.
The club has said Hassli, who made US$790,000 last season as a designated player, remains under contract but it will try to move him if requested.
Toronto's Kyle Bekker, Terry Dunfield, Doneil Henry, Ashtone Morgan and Matt Stinson have been called up by Canada for a national team camp in Arizona.
Toronto captain Torsten Frings, whose 2012 season was cut short by hip surgery, was among the players present at camp Saturday.
Payne is in the process of remaking a club that has never made the playoffs and finished last in the league in 2012 with a 5-21-8 record.
Ten players have left the club since last season. Seven have come the other way and Payne, reinforced by some allocation money obtained during draft day deals, says he has his eye on more new talent.
TFC has scheduled its media day for Tuesday. The team heads to Orlando on Feb. 1 to continue training camp in the warmth of the Sunshine State.Suggest a correction