The `Gravity` hitmaker has been placed on "complete vocal rest" for at least a month to help with his recovery after having a granuloma - a non-cancerous lesion that results from continuous irritation - removed from just above a vocal cord.
He revealed on his blog: "It`s been a very long process in waiting to see if time was an alternative to surgery, but even given two weeks` voice rest (along with many other approaches), there was no change for the better."
The problem caused him to postpone recording on his new album, and John admits he is "dreaming" of returning to work - but planning on making the most of his time off by taking a holiday.
He added: "I should be frustrated but I can`t seem to stop thinking about beautiful things... I never thought I`d be wishing I could do what I love again; I stay in at night, picking guitar parts off of records and dreaming of playing on the big stage. The only difference between now and when I was 18 is that now I have this beautiful, meaningful record waiting for me when I can sing it.
"Until then, I`m taking off. Going to travel the country, look and listen."