He was willing to defend his title against Callum Smith with a July 1 showdown at The O2 having been agreed, only for his domestic rival to opt for a shot at the vacant WBC belt against Anthony Dirrell in September.
"It has been a frustrating few months since I drew with Badou Jack in New York, and I had hoped to have announced my next opponent by now," DeGale told The Mirror.
"But tomorrow [Wednesday] I will have surgery on my right shoulder that will mean I will be out of the ring for a while. I suffered the injury several weeks before I fought Rogelio Medina but decided to fight through the pain, as I did earlier this year against Badou Jack.
"I was only operating at 60 to 70 per cent however and that showed against Jack. Thankfully I've been good enough to get away with not being at my best, but I was almost found out in New York.
"The operation is for 'a scrape and tighten up', or a 'diagnostic arthroscopy and ACJ stabilisation' to give it its medical term. Within eight to 10 weeks I should be able to spar. I will definitely be able to fight before the end of the year.
"I've been plagued by injuries for the last few years. These haven't been niggles, they've all required operations. People have been commenting on my performances -- saying I wasn't fit or that I wasn't at my best -- but it's been a long time since I've gone into a ring at 100 per cent."
An obvious future opponent for DeGale is George Groves in a rematch to their 2011 clash that was won by his old rival via a majority decision.
Groves is now WBA champion after stopping Fedor Chudinov last month, but DeGale was unimpressed by the performance and insists a second instalment is far from certain.
"I didn't think Groves looked great. He didn't fight the best world champion and I think Groves has gone backwards," DeGale said. "I'm not being disrespectful but he's not got the same sharpness or attitude he used to. I don't think he deserves a 50/50 split.
"Negotiations will be difficult and the terms will have to be right for the fight to be made."