Gunners manager Arsene Wenger has condemned the tackle as "horrendous and unacceptable", while also criticising Stoke's overall approach.
Republic of Ireland midfielder Whelan had a first-hand view of the incident, helping comfort the Arsenal youngster as he lay in agony.
"First and foremost, everyone hopes the young lad gets back as soon as possible, and at the standard he plays at, because he looks a terrific player," said Whelan, who was co-incidentally at Arsenal's London Colney training base on Monday afternoon preparing for Tuesday night's friendly international against Brazil at the Emirates Stadium.
"I was the next one in from the tackle, and saw what had gone on. I was just trying to take the lad's mind off it.
"For Shawcross, he was disappointed what has happened to the boy.
"I have not seen the tackle again but when I first saw it, I do not think it was a dirty tackle - maybe a bit late but no more.
"I do not think anyone goes into a tackle looking to break a leg or injure a player, but there is fine line between being hard and being dirty.
"The two players could go in for that tackle 100 times again and nothing would happen. Hopefully this was just a one-off."
Whelan has not seen the incident again - and does not want to.
"You have got young people watching the game live, who probably could not stomach something like this, and so they were probably right not to show it again at the time," the midfielder said.
"I have not seen the tackle again, and if it came on, I would probably turn the television off.
"It was the first time I had seen it, and touch wood it will never happen again.
"I was just there, and if I was on the other side of the pitch, I would probably have not gone anywhere near him.
"I was just trying to do what I could to take the lad's mind off it.
"The lad held onto me with the pain he was going through, and I was telling him not to think about it. He was in a state of shock.
"The medical team came on as quickly as possible, and then you just let them take over."
Chelsea 3/10, Draw 4/1, Stoke 9/1