Gerrard sympathised with Shelvey after his dismissal for a lunge on Jonny Evans.
Manager Brendan Rodgers felt either both or neither player should have been sent off as both tackles were equally as bad and Gerrard agreed.
"I feel for Jonjo a bit because it is a big game and these big games are about big tackles," he said.
"I don't think he got the tackle wrong because if his tackle is wrong Evans' tackle is wrong as well.
"That is the consistency we are looking for in referees and Mark Halsey's got that one wrong."