The £18m summer signing from CSKA Moscow has been told a change in climate or even diet could be the reason for swelling that has limited him to about 90 minutes of football for the Blues this season.
Injury to left-back Ashley Cole could give Zhirkov the chance to make his mark at Stamford Bridge, but the 25-year-old must first come through the second-leg of Russia's World Cup qualification play-off in Slovenia.
Mind the knee: Yuri Zhirkov rides a challenge when lining up for Russia against Slovenia at the weekend
'I will not hide that my right knee continues to bother me,' said Zhirkov in the run-up to the game in Maribor, for which Russia hold a 2-1 lead.
'The pain goes away and then reappears. Hopefully I will be all right.
'I am always happy to help the (national) team. Before the match at the Luzhniki I said that I was ready. Fortunately, the coaches trusted me with a place in the team.
'Of course, I want very much to play as soon as possible for Chelsea. I'll do everything I can.'
Zhirkov hurt his right knee in pre-season against AC Milan, though it is thought the problem may have been the result of playing for years on the artificial pitch at Moscow's Luzhniki Stadium.
He has since felt pain in both knees and suffered swelling after playing for less than 20 minutes as a substitute against Atletico Madrid in the Champions League last month.
Frustration: Zhirkov has struggled to be fit for Chelsea boss Carlo Ancelotti (right)
Chelsea doctors have been so baffled that they have consulted experts in France and Germany while working on a number of theories as to the source of the problem.
Out of action: Ashley Cole is set for a spell on the sidelines
'The English doctors see my problems as a reaction of the body to drastic changes: in the climate, lifestyle, training work and in everything else,' he said.
'And no one can tell me what the medical predictions of my rehabilitation are.
'The British physicians even consulted with German specialists regarding me.
'They sent them my X-rays together with the detailed description of the problem but, as far as I understand, they failed to diagnose the problem.
'I try to remain optimistic: many players have had such difficulties. I am not the first, not the last. It is a pity that the problems coincided with my move to a new club.
'But if I keep being distressed the situation will not change. I must work and believe that everything is going to straighten out soon.
'In Chelsea the team is very good, all of them understand my situation. My case is not the first one, many newcomers of Chelsea were sidelined in the first months at the club.'
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