The Swedish international was stretchered off in the second half after going down and initially being attended to by the physio.
The extent of the injury won’t be known until he undergoes a scan and is fully assessed by the Rangers medical team.
It is a worry for Rangers, with their Europa League tie against Lyon on Thursday night. They also had to do without fellow centre-half Connor Goldson in Perth, who was isolating.
On Helander’s injury, Gerrard said: “I’m concerned. He’s with the doctors now. He’s got ice on it and is bandaged up. It doesn’t look good.
“But until we scan it and assess it in the next 24-48 hours time, we’re not too sure.
“Fingers crossed he’ll pull through, but we’ve got other defenders who’ll need to step up if he’s out for the short, medium or long term.”
The Ibrox boss commended his way on once again showing the mental strength of champions after coming back from a goal down.
Michael O’Halloran, a former Rangers player, gave Saints the lead, but a Kemar Roofe penalty and a fine individual goal from James Tavernier meant the points were going back to Glasgow.
Gerrard compared the win to the 1-0 derby victory over Celtic before the international break as his team returned to the top of the table.
He said: “We were coming up against a really organised team and we knew we’d have to show real quality at the right time to earn the three points.
“First half, I didn’t think we did much wrong, but we didn’t have that bit of magic or quality in the final third.
“Second half, we go a goal down and it becomes a little more complicated. But that’s what champions do, they find ways and they find answers. That’s what we’ve done today. It’s a credit to the players.
“In any game of football that’s a world-class finish from James. We also had a bit of quality in the build up to the penalty. It was us pushing, knowing that we were 1-0 down and our big players needing to step up for us, and that’s just what happened.
“We’re champions for a reason because we’ve got good players, but we also know how to win.
“We’ve had to go late and deep to find a way against Celtic and we’ve done it again today.”