Rangers travel to Russian Federation this week for a crunch Europa League clash with Spartak Moscow where they can take a huge step towards qualifying for the knockout stages.
Speaking in his pre-match press conference, Gerrard said: "Ryan is struggling with a hamstring and the earliest we will see him is after the worldwide break if everything goes well".
"Obviously it's an opportunity for someone else, certainly over the next couple of games, to come in and express themselves". But there's no getting away from it that it's a big disappointment for myself and the team because Ryan has been in fantastic form and is a real threat for us.
"They are in a bit of turmoil, manager has been sacked, the players don't look happy, so Rangers have got a good opportunity".
"And Kyle still has an issue with his quad muscle which prevented him from travelling".
Spartak also have their troubles, with supporter unrest hanging over the club.
"We can only hope that the atmosphere is the same in the stadium because that would mean we are playing well and we're doing our job", said Gerrard, whose side lead the group with five points.
"We don't want to play in a shell like we did in the first 45 minutes at Villarreal".
Gerrard also noted Riancho's comments that his side will be more attacking after holding Rangers to a goalless draw at Ibrox.
A win in Moscow would put the Gers in a strong position to make it through to the next round, although they will have to do so without a number of injured players. Whether they decide to go gung-ho or have a more patient approach, we'll have to wait and see.
It's not long now until the Gers are back in European action and I know plenty of us are rightly excited about the game tomorrow night.
"But we do realise Spartak have very unsafe players, good players. And if that's the case, we have to be ready for it".