Manager Jos Luhukay believes his returning Wednesday stars Kieran Lee, Steven Fletcher and Gary Hooper are like "new signings".
Midfield dynamo Lee and forwards Fletcher and Hooper have not played a match in over six months due to injury.
But the trio, together with the rest of the Owls squad, reported back for pre-season last week and are understood to have joined in with a number of the lighter training sessions.
Luhukay, who has yet to add to his squad this summer, told The Star: "It does feel like we have new signings.
"They are a couple of players I have not worked with before. I'm interested in the quality of these players."
Lee and Fletcher are ahead of Hooper on the comeback trail, according to the Dutchman. But Luhukay was hopeful Hooper would step up his recovery in their second training camp this week.
He has sounded a note of caution with Lee, Fletcher and Hooper, saying: “They have been away from the group for a long time and from training and from games.
"When they can start 100 per cent training with the team, they can bring themselves in a better position in a physical and football direction.”
Wednesday have arranged just three warm-up matches. Their friendly programme consists of away assignments against Lincoln City and Mansfield Town followed by Hillsborough clash with La Liga side Villarreal on Saturday, July 28.
Luhukay's side are also due to face Dutch club NAC Breda in a behind-closed-doors fixture this month.
"We have a couple of friendly games but we can play 11 against 11 in the training sessions every day," said Luhukay. "We can be very flexible with our work."