Roach started training Khan nine months ago
Amir Khan's trainer Freddie Roach has slammed the Bolton fighter's opponent Andreas Kotelnik for postponing their WBA light-welterweight fight.
The pair had been due to meet at London's O2 Arena on 27 June but will now clash three weeks later on 18 July at Manchester's MEN Arena.
Kotelnik, from Ukraine, rescheduled the fight because of a tooth infection, which apparently needed minor surgery.
But Roach said: "You can't have surgery and recover in two weeks - come on."
Roach believes that a lack of preparation is the real reason the 31-year-old put back the fight.
"I'm very disappointed because he pulled out with toothache," added the American.
"I'm not a doctor but, if you have surgery on a jaw tooth, it takes more than two weeks to heal.
"Kotelnik's just not ready - he looks a bit soft and is not in shape."
Kotelnik, who has lost just twice in a 34-fight career, was apologetic for the delay but vowed, as he has all along, to knock Khan out.
"I apologise for the rescheduling of the fight," said the 31-year-old.
"It was an accident that happened while I was sparring. My teeth got broken and the doctor said I had to rest.
Kotelnik and Khan had been due to fight on 27 June
"I will have another operation on my teeth on Friday in Ukraine and then everything will be fixed.
"I will start my sparring when I get back to Germany and I will be ready to fight on the 18th. It will be a tough fight for Khan."
Roach, however, is confident that following his work with Khan at his Wild Card Gym in Los Angeles, the 22-year-old is ready to become a world champion.
Khan has been beaten just once in his 21-fight career, with that defeat coming in September 2008, when he was beaten inside a minute by Breidis Prescott.
"When I took Khan over nine months ago after the Prescott fight, everyone thought he was ruined - he made a fundamental mistake and paid for it," said Roach.
"But he's a great athlete and a great fighter, I think he's the next superstar here in the UK.
"Nothing's easy in life, I know Kotelnik isn't going to be, but I truly feel we'll knock him out."
I was a bit angry, but it's sport, it's going to happen - but over toothache? Come on
Khan also admitted to being annoyed at the delay of the fight, but has vowed not to let it stop him from realising his dream of becoming a world champion.
"I was a bit angry, but it's sport, it's going to happen - but over toothache? Come on," said Khan.
"It must have been been a very serious one. I saw him today (Thursday) and he looked ok, he was chewing gum and seemed alright, so maybe it was tactical.
He added: "It's only a three week delay from the original date, so I'll still stay focused.
"I'll be motivated because it's for a world title and I really want to win one, so nothing will stop me.
"It's just another delay to me being a world champion."