The Bluebirds supporter fell out of the top tier of the away stand into the seats below as the visiting fans were celebrating Chris Burke's 48th-minute opener for the Welsh side. The male fan fell 15 feet and was taken to hospital with head and neck injuries, Millwall said in a statement.
The club said he was in a stable condition. All the goals came in the second half, Liam Trotter with a penalty, Kevin Lisbie and Steve Morison netting for the Lions, Burke scoring twice and Peter Whittingham once for City. But Jones' thoughts were with the injured fan, saying: "I couldn't give two hoots about the result after that. One or two of the players saw it and Craig [Bellamy] said it made him feel physically sick.
"We don't know much about him but all we'll say is that we as a club send our best wishes for a speedy recovery. We desperately want to do well for our supporters and as a club we have a duty to them. At the moment, we are all just concerned about that guy."
Source: PA