Ospreys duo Mike Phillips and Gavin Henson have responded well to surgery and are on course to return at the end of September in time to be available for Wales' autumn internationals.
Phillips underwent an Anterior Cruciate Ligament reconstruction to the right knee at the start of April while Henson had keyhole surgery on damaged ankle ligaments to stabilise the joint in late April.
The pair will be eyeing the RBS 6 Nations holders' four remaining Tests this year against South Africa, Canada, New Zealand and Australia, all at the Millennium Stadium in November.
Young Ospreys flanker Ben Lewis, who was due to tour South Africa last month, also underwent an ACL reconstruction on his right knee in mid-May and should return to action in November.
Ospreys physio Chris Towers said: "An ACL reconstruction will always require somewhere in the region of a six month rehabilitation programme, and Mike is three months into it.
"He is recovering well and at this stage is easily achieving all his targets in terms of physical recovery and is starting to develop his strength and power.
"Over the next week or so he'll resume controlled skill sessions, but he is still a long way from full contact work. He is on target to return at the end of September or early October."
Towers added: "Gavin is still in a walking plaster, which is scheduled to come off on the 10th July. Once it has been removed then we'll be looking at working closely with him to get it functioning properly.
"The indications are that the ankle is coming along well and we are looking towards Gavin returning to action towards the latter end of September.
"Ben is just six weeks into his post-op rehab but is responding well and is on course for the standard six-month return to action for an ACL reconstruction, which would see him return to action in November."
In addition, Lee Byrne, Nikki Walker and Andrew Millward have all undergone minor operations, and having recuperated well over the summer will take a full part in pre-season training.
The 2017 RBS 6 Nations was watched by record numbers of fans
29 March 2017, 12:25pm
After an enthralling RBS 6 Nations Championship of twists, turns, and no small amount of drama on the last day, figures show the RBS 6 Nations is going from strength to strength, year on year, with no sign of slowing down.