Perry, 29, sat out Friday's session but eased fears over his fitness by playing a full part as England were put through their paces at the St David's Marist College in Sandton, Johannesburg.
He is competing with Pete Richards and Andy Gomarsall for the chance to play South Africa in next weekend's first Test in Bloemfontein.
For Gomarsall, this tour represents an unexpected opportunity to press his claims for a place at a third World Cup.
Last August he was dumped by Worcester just 12 months into a three-year deal, leaving him unemployed and with twins on the way.
Offers of work hardly came flooding in and Gomarsall had to start pondering retirement before Harlequins offered him a lifeline.
The move to The Stoop resurrected Gomarsall's career - and he is determined not to let this unexpected chance slip through his fingers.
"At the start of the season I would have never believed that I would be where I am now," said Gomarsall, who was involved with England at both the 1995 and 2003 World Cups.
"In August last year I had no club and while I set myself goals, and being back with England was one of them, I knew at that stage it was a distant possibility.
"I'm indebted to Harlequins and Dean Richards who took me on this season, and grateful to Dean who is always pushing his players forward for international honours.
"It's now up to me to take any opportunities that come my way and I'm determined to enjoy every moment."
England head coach Brian Ashton is without around 40 players for the tour, most of whom are involved in European finals this weekend with Bath, Leicester and Wasps.
But Gomarsall is revelling in the environment and insisted: "There is a great spirit here amongst the squad and everyone is very positive.
"Brian Ashton is doing a good job. I'd heard from the other players that the sessions were excellent and it was good to be part of them and see that at first hand."