Chelsea striker Andriy Shevchenko has raised concerns over his future at Stamford Bridge once again after he said that he was at his happiest while on international duty, according to Daily Telegraph.

Ukraine international Shevchenko came off the bench to replace two-goal Didier Drogba in Rosenborg last night as Chelsea ensured their passage through to the knockout stages of the Champions League with a 4-0 victory.

He had hoped to establish himself in Chelsea`s starting line-up following the departure of Jose Mourinho. Since Avram Grant has taken over, Shevchenko remains to be left on the sidelines and continues to lose patience in west London.

"I`m not happy but what can I do?" Shevchenko told a Croatian newspaper. "I`m quiet and work hard in training every day."

While Shevchenko struggles to score in the Premier League - he has only scored five goals since his arrival in 2006 - he holds an impressive goals-per-game ratio on the international stage.

"The biggest joy for me is playing for Ukraine," the 31-year-old said.

"Every time I`m with the national team, I recharge my batteries which run low in London because of the things that are happening to me.

"I`m very happy when I`m at home and I just can`t wait for the next games."

Shevchenko is likely to go up against some of his Chelsea team-mates in Frank Lampard, Joe Cole, Ashley Cole and Shaun-Wright Phillips when Ukraine face England in their 2010 World Cup qualifier.

Despite England`s failure to reach the Euro 2008 finals, Shevchenko believes they will come back stronger and are favourites to top the standings to book their spot at the tournament in South Africa.

"England are the best in our group. Just look at which clubs the England stars are playing in.

"England didn`t qualify (for Euro 2008) but they are still one of the strongest national teams in Europe. In my opinion, something like that will not happen again for England."