"I missed everything - the tournaments, the fans, the stadiums, the other players, I really missed everything," he said.
"But now I'm here again and I'm trying to play a good level. Everything was difficult after my surgery, but those bad things are the past. Now I am having a good 'present', I'm healthy, and if I work and still improve my game, I will have a good future."
Wimbledon is the most important tournament of the year for me
Del Potro lost to Nadal on his only previous appearance
at Queen's Club in 2007
and is determined to improve on grass.
"I like London, I played at the Aegon Championships a couple of years ago and I really enjoyed it," said Del Potro.
"If you want to be a really good player you have to win on grass courts. I never had good results on grass before so this year could be a chance for me to improve my game on grass at Queen's and at Wimbledon.
"I have to learn many things on that surface but I will be ready to do it. Any tournament I play I want to win and If I can play my best level I think I can do it."
Roddick won the title at Queen's Club in
putting him alongside John McEnroe, Boris Becker, Lleyton Hewitt, Roy Emerson, MJG Ritchie and AF Wilding as the only four-time winners.
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