Trundle will now remain with Leeds until March 10 but City can recall the forward provided they give United 24 hours notice
City boss Gary Johnson said: "We have hit a bit of form recently and having a settled squad Lee has been playing games for Leeds.
"I know Lee is enjoying himself at Elland Road and now he gets another month there. We have also got a 24 hour recall clause if we need to use it and things change there. I think the situation works out well for everyone concerned."