Clarke collapsed during the second half of Leeds' thrilling 1-1 draw with Middlesbrough at the Riverside.
A massive 11 minutes was added after regulation time of 90 minutes and this could be explained with centre referee Darren England having to reach out for his whistle 20 times as Boro committed 11 fouls while Leeds committed 9 fouls in the course of the game with two yellow cards going to Boro and one for Leeds.
Fortunately for all involved, Clarke has since been released and given the all the clear after feeling unwell during the away game.
"The player is responsive and attending hospital with the club's head of medicine and performance".
Former Leeds defender Ian Harte, who represents Clarke, revealed the 18-year-old had been discharged from The James Cook University Hospital and thanked the medical teams from both sides.
Pulis said: "I was more concerened about Jack Clarke and I hope he is okay".
Marco Bielsa, meanwhile, addressed Clarke's situation at the final whistle.
Leeds chief executive Angus Kinnear told the club's official website: "Jack has had messages from football fans from every club you can imagine and we all really appreciate it. We don't know the reasons yet", he said. He was swiftly given oxygen and after a lengthy and concerning spell of treatment was taken on a stretcher to the dressing room.