The striker, who joined Leeds on a free transfer in the summer after scoring 29 goals for League One rivals Swindon Town last season, has seen his frustrating absence extend into the third month of the Championship term and he appears no closer to making his competitive debut.
Paynter played in two pre-season friendlies, his only public outings to date, but was reported to have suffered a stress fracture to one of his shins, a claim which remains unconfirmed.
His attempt ats a comeback last month ended in failure following an appearance in a behind-closed-doors friendly at Thorp Arch, a match which led to fresh doubts about his condition.
Simon Grayson said: "He needed another scan and after the weekend we should know where we are. He'll be fresh when he finally does comes back, but it's frustrating for him.
"He looked strong in pre-season and I thought we were getting somewhere with his fitness, close to getting him back into the first-team squad. Obviously he's had a setback, but we'll know more next week."
His rehabilitation is likely to run well into this month, but Leeds do not have another fixture until October 16 when they travel to face Gordon Strachan's Middlesbrough.
Grayson added: "We'll have a lot more players available by the time we come round to that game."