A confidential letter to fund shareholders from Mr Soros, obtained by The Independent, says Mr Roditi "had a previous health issue and he has asked to take a rest as a precaution against any recurrence".
In the letter, sent out on Friday, Mr Soros says Mr Roditi, reported to have earned pounds 80m in 1996, is taking this step after "six tiring and very profitable years".
Colleagues say that Mr Roditi, 54, one of few people allowed in to Mr Soros's inner circle, is the financier's "most trusted advisor" and that the illness has been a big blow.
Returns on investments in Mr Roditi's Quota Fund have averaged 48 per cent since the fund was launched in January 1992, making it the best-performing fund in the Soros stable. The firm admits that because of the recent market turmoil the fund is down 13.64 per cent in the year to date.
Because of Mr Roditi's absence assets from the Quota Fund, currently "very liquid", will be reallocated "on an opportunistic basis".
The firm has brought forward plans to merge Mr Roditi's other fund, Quasar International, with the main Soros fund Quantum International. These two will for the time being be managed by Stanley Druckenmiller, now responsible for day-to-day management of the Quantum fund.
The firm has decided to "recommend termination" of the Quantum Emerging Growth Fund, Mr Soros's main emerging markets and growth companies vehicle, which is down 30 per cent in the year. Mr Druckenmiller admitted in August that the firm had lost $2bn in the Russian bond debacle.
Mr Soros says in the letter that he hopes Mr Roditi's absence "will be of short duration". Mr Roditi has said to be willing to manage part of the combined fund on his return.Reuse content