He is managing director of Meon Valley Stud which owns the Hughie Morrison-trained colt who came to prominence when winning the Dante Stakes a fortnight ago.
Connections only decided this week to supplement the three-year-old – the mount of in-from Oisin Murphy – for this Saturday’s blue riband race.
“The decision was painful, I’d say,” said Weinfeld.
“It wasn’t taken lightly – we had to be absolutely satisfied that the horse was ok after he breezed on Monday.
“Anthony Oppenheimer faced a similar situation with (2015 Derby winner) Golden Horn – so we’re hoping for a similar outcome!
“I just hope he runs well, and to the best of his ability.”
Telecaster, who made his racecourse debut at Doncaster earlier this year, is a leading contender for the Derby and Weinfeld added: “I’m pinching myself and I have to keep asking if I’m dreaming – it’s a great moment.
“Telecaster is bred for the job, we hope. We had a few offers for him before the Dante, and we said we’d follow them up if we were interested, but once he won at York we felt we’d got this far – so we may as well enjoy it and see where we go.
“I think it would be a lesser race without him. The Dante is the premier Derby trial really, so if the winner of it isn’t in the Derby it dilutes the race.
“We hope there’s no doubts about his stamina. You just never know with breeding. We may as well find out in the Derby.”
Meanwhile, Enable is set to make her long-awaited return in the Coral-Eclipse at Sandown in July after connections ruled out an appearance at Royal Ascot.
John Gosden’s dual Prix de l’Arc de Triomphe heroine has been kept in training as a five-year-old, with the chief aim of becoming the first horse in history to win Europe’s premier middle-distance contest three times.
York Racecourse chairman Teddy Grimthorpe, also racing manager to Enable’s owner-breeder Khalid Abdullah, said earlier this month the star mare would sidestep this week’s Coronation Cup at Epsom and instead be aimed at either the Prince of Wales’s Stakes or the Hardwicke at the Royal meeting.
However, a workout in Newmarket yesterday has prompted another change of heart. “Following a piece of work on the Limekilns this morning both John Gosden and Frankie Dettori feel that Royal Ascot will come too soon for her,” he said.