He was picked in an extended World Cup squad, but a calf injury halted his progress until Sheridan went home injured.
Waldrom was called into a meeting with Tigers coach Richard Cockerill at Welford Rd, expecting to go through a review of his work.
Instead the coach told him to pack his bags and skedaddle out to the World Cup on standby. That temporary role became permanent this week.
Cockerill was a man of "wise wisdom" who was not going to deny his No 8 a rare opportunity even though the club was struggling for results.
Waldrom understood his long flight might end in disappointment, but he acknowledged it was a chance few received. He knew the deal and was delighted to make the trip. His ambitions now were to train hard, learn the team moves and see whether he could impress the selectors to get a place in the starting 22.
"We just have to see what happens," the 28-year-old said.
He spent five days waiting for his official call-up, training hard away from the squad, getting over his jetlag and indulging in a few local delicacies, like Toffee Pops.
He said rugby in England was different, more intense, and he was working hard at Leicester to improve.
He had noted the All Blacks' progress and reminded us England were doing something similar.
Waldrom had spoken to his parents, but had been unable to reach All Black brother Scott, who had been involved in some television commentary work.
Injured England No 8 Nick Easter was improving but in the meantime Waldrom said he was going to get stuck into as much training as possible and send out some "pick me" messages.
"It is a bit crazy, but enjoyable."
ENGLAND v SCOTLAND
Eden Park, Saturday 8.30pm