In his column on SARugby.co.za he said that Pienaar's ankle and Steyn's knee problems were improving.
"It was encouraging to see the likes of Ruan Pienaar and Frans Steyn running again after their injury lay-offs. They will continue to receive treatment in the days ahead to ensure that they will be fit for selection ahead of the first Test," he wrote.
"The good news from the medical and conditioning team is that they expect a fully-fit squad by that time. With the initial groundwork done, the full squad of 28 will hit the ground running in Durban next week as we intensify preparations for the first Test.
"The initial part of our preparations for the British & Irish Lions Test series is over and I am satisfied with the progress we have made over the past two weeks."
De Villiers gave his victorious Super 14 Bulls players a bit of a break and the rest of the squad were given a weekend off before getting down to the business of trying to win the series against the Lions.
"It was imperative that we gave the Vodacom Bulls players the past week off to allow them some rest after their tough Super 14 semi-final and final matches," added de Villiers
"The encouraging thing for me was that all of them came through those two matches without injury which is a great confidence booster. With the Vodacom Bulls putting their feet up after their stunning victory we were afforded the opportunity to work with the balance of the squad to test their levels of fitness, assess and treat players carrying injuries, work with the kickers, test out some new plays and formulate our game strategies.
"The Lions looked good in midweek and we are expecting the Test series to be very tough. It is going to be a great contest and one that our entire squad is looking forward to."