Celtic can close that gap to three points if they beat Dundee tomorrow night.
As Gerrard and midfielder Jordan Rossiter, whose Rangers career has been plighted by injury since his 2016 move from Liverpool, greeted the press on Tuesday ahead of Wednesday's Scottish Premiership clash with Kilmarnock, the manager's comments were referenced by reporters.
"The business I am in, it is cut-throat, it is brutal", said Gerrard. "It's a warning. That's for me - not him". He's been injured for two years.
"That's the way it is, we're at a big club and big clubs requires big players who step it up in big moments on big occasions".More news: Coleman: Everton can take positives from United defeat
Gerrard was disappointed after a timid performance from his side and warned the players in his squad that he won't think twice about replacing them with better quality players in the future. "If they're not with us right now, I'll find them".
"I wanted a reaction tonight, so that is the disappointing and frustrating thing. What should I have done differently?"
His next challenge is up against Killie manager Steve Clarke, first-team coach during Kenny Dalglish's second reign at Liverpool, and victory would show Rangers' response to his delivery.