If you consider the Hoff looked a little, err, off in his short spell on Dancing with the Stars, you had explanation to think so. E! News has wholly learned that David Hasselhoff undergo a minor surgical process Monday morning. Hang on, it's not what you feel...The 58-year-old actor required a quick trip to the doctor this week to have liquid tired from his knee and was wearing a brace during his performance, his manager Larry Thompson told E! News that Hasselhoff had been receiving cortisone injections in his chronically sore knee, which was ballooning during rehearsals for his DWTS debut. The swelling got so bad by Monday, Thompson says, that it necessitated going under the needle to remove the fluid."He's upset he didn't win," Thompson says, "but he's relieved he doesn't have to dance on it [anymore]."And Hasselhoff isn't using his injury as "an excuse. It's the truth."Regardless, the former Baywatch and Knight Rider hunk will be back in his comfort zone tonight, when he begins a four-night concert engagement at the Riverside Casino in Laughlin, Nev."It's easier to sing on his knee than to dance on it," Thompson says.