Scimeca, also a former Foxes player, failed to appear for the start of the second half with debutant Darcy Blake replacing him.
But Cardiff manager Dave Jones was hopeful the 31-year-old would quickly be given an all-clear by doctors.
Jones said: "He was taken to hospital at half-time because he was coughing up blood.
"We were worried he might have had something on the lung but, fingers crossed, he should be okay.
"He landed on his back after going over the top of one of the Leicester players and he got a bang on the lung.
"We were frightened he might have punctured the lung or broken a rib but we are hopeful he will be given the all-clear and will be straight back in training tomorrow.
"But Darcy Blake came in and had a great debut, I thought he did really well.
"On top of Riccy though we have also got Stephen McPhail with a tight hamstring and I took Kerrea Gilbert off because he had a tight groin.
"He did not want to come off but it was his first game in two months since a dislocated shoulder.
"Willo Flood could not play today because bruising from his ankle has moved all the way up to his neck."
Cardiff were earlier this week saved from financial collapse by a consortium fronted by chairman Peter Ridsdale and Jones confirmed the Ninian Park board had now given their backing for transfer-window signings in January.
Jones said: "The takeover is a massive step forward for the club because today we could have been in administration.
"But I have to move very quickly in the window because if I am moving then you can bet 16 or 20 other managers will be trying to get the same players."
Meanwhile Milan Mandaric's proposed takeover of Leicester has stalled as lawyers and accountants continue to pore over the Foxes' books.
And manager Rob Kelly said the uncertainty meant he could not count on making any new signings of his own.
He said: "I have absolutely no idea whether I will be able to make any signings.
"It all depends on the takeover and it would be nice to get that settled.
"I am as much in the dark as everyone else and at the moment can only affect things on a day-to-day basis."
The 0-0 draw left Cardiff sixth in the Championship table but without a win in seven games while the Foxes remain seventh from bottom.
Matty Fryatt had the ball in the net but the Foxes frontman saw his second-half strike disallowed for offside.