Looks like it is not a severe injury, just a ligament strain. Seems like he is targeting a return for DC, hopefully he isn't rushing it, but obviously it's hard to say without knowing more details.
“It was an unfortunate situation in yesterday’s match, but (I'm) looking forward to returning to Wimbledon in 2012," he said. "I have since been working with the doctors, and I strained some ligaments around my hip and doing some more tests just as a precautionary measure. I am hopeful that I will be back practising in the very near future and looking forward to Davis Cup."
Good news, I was worried that it could have been a more substantial hip or groin injury.