Pakistan's limited-overs captain Shahid Afridi described Yasir Hameed as having the mental age of an adolescent on Sunday night.
Thirty-two-year-old Hameed was quoted in Sunday's News of the World, accusing his Pakistan team-mates of trying to lose matches for apparent financial gain, although he later released a statement insisting he was only repeating allegations he read in the newspapers.
But Afridi, whose team lost their NatWest International Twenty20 opener against England in Cardiff by five wickets on Sunday, claims Hameed - not part of the limited-overs squad - is an unpredictable character.
"I think he is 30, 31. But mentally he is 15, 16," he said.
Asked whether Hameed can be unreliable, he added: "Yeah, the people know which type of character he is."
Hameed played in the final two Tests of this summer's series against England, which ended at Lord's.
It was during that match that News of the World claims surfaced - alleging Test captain Salman Butt, Mohammad Asif and Mohammad Aamer were part of a plot to assist illegal bookmakers by arranging to bowl no-balls to order.
All three have since been charged and suspended by the International Cricket Council's anti-corruption unit (ACSU).
A follow-up report in the Sunday tabloid this morning quoted opening batsman Hameed, apparently incensed at his team-mates' behaviour. Afridi added: "I don't know with whom he was sitting or in which situation he gave this message.
"I don't know, but we have known him for a long time and we can expect anything from him.
"He has been doing these type of things a lot of times."
Hameed's statement was read out by a spokesman on the steps of the Pakistan High Commission.
In it, he explains the circumstances in which he spoke to a News of the World reporter - whom he did not recognise as such at the time, because he was under the impression he was being offered a sponsorship deal rather than asked for an interview.
"Naturally, I was interested in what he had to say - and we began a conversation," he recalls in the statement.
"He offered me at least 50,000 pound for the deal.
"As I saw him as a friend and a potential agent, I naively started to answer his questions.
"As far as I recall, I only told him whatever I had already read in the newspapers about the matter."
Hameed said he later received a mobile phone text from the man, which read: "Please call me. Incidentally you are on video drinking wine and saying all the quotes.
"Denying it is just stupid, and we will be releasing the video to TV. Better that you just stand up and speak the truth."
This morning, the News of the World also claimed a fourth Pakistan player - unnamed 'for legal reasons' - is being investigated by the ACSU.
The world governing body are unable to confirm or deny the existence of work being undertaken by the ACSU.