The Bulgarian forward, who has been sidelined since August with a cruciate knee ligament injury he sustained whilst on international duty, made a 45-minute appearance for City's reserves side at Newcastle on Monday and could make the squad for the 1st leg away tie in Hamburg on Thursday.
"The plan was to give him 45 minutes on Monday night," City boss Mark Hughes has said. He came through that and looked impressive.
"You forget what quality he can produce and he looked in good nick.
"He was blowing a bit, which is fairly obvious given how long he has been out. But he is an option for us."
"When I came in as manager, the fact that Martin was available to me was a big plus..
"I had watched him from afar the year before and saw the quality he could produce.
"The opportunity to work with him was something I was looking forward to but unfortunately we lost him very quickly, which was a big blow to us.
"When you see what he can produce you can see what we have lacked on occasions this season."