The news comes from unearthed interviews with band member John Lennon, which were recorded in January 1969.
In the audio, the frustrated "Imagine" singer calls Harrison "a festering wound" and adds, "We allowed it to go deeper and we didn't even give him any bandages."
Lennon goes on to suggest that his place in the band should be taken by fellow guitarist Clapton, stating, "I think if George doesn't come back by next week we ask Eric Clapton to play."
The revelation comes from more than 120 hours of unheard audio and 50 hours of unseen footage captured by director Michael Lindsay-Hogg during the rehearsals and recording of what became the Fab Four's final album, "Let It Be". The recordings are to be used as part of a new documentary to mark the 50th anniversary of the album reaching the top of the charts.
The three-part TV documentary, titled "The Beatles Get Back", has been put together by Peter Jackson, the Oscar-winning director behind the "Lord of the Rings" trilogy.
The project is scheduled for release on Disney+ in November (21).
Meanwhile, Harrison and Clapton's longtime friendship was tested in the early 1970s when the "Layla" hitmaker stole the late Beatle's girlfriend, Pattie Boyd. The couple went on to wed in 1979.