Steven Gerrard said artificial turf has no place in "elite football" after seeing one of his Rangers players injured in a game at Kilmarnock on Sunday.
Rangers winger Jamie Murphy fell to the synthetic surface in the 17th minute of the club's 3-1 Scottish league cup win, and Gerrard, who is still unbeaten as a manager after nine games in all competitions with Rangers, was asked if the pitch was to blame for the injury.
"It's difficult for me to comment on [whether the pitch caused the injury]," the former Liverpool captain said. "We all know that plastic pitches are not as safe as grass.
"But I'm not here to disrespect Kilmarnock and their playing facilities. I know it helps support the running of their football club. But my opinion is elite football shouldn't have any plastic pitches."
Gerrard's comments came one day after Zlatan Ibrahimovic made headlines by skipping the LA Galaxy's trip to the Seattle Sounders to avoid testing his surgically repaired knee on artificial turf.
And Gerrard, who played four games in Seattle during his two seasons with the Galaxy, said the risk of using turf was not worth potential financial savings over grass pitches.
"We're dealing with elite footballers, who earn an awful lot of money, and I think for every club worldwide it's safer to have a grass pitch," Gerrard said. "We'll have to wait and see. I think if you ask Jamie right now he'll say it was a pitch incident.
"I don't think it's the first time Rangers have had that type of injury here, I think [Martyn] Waghorn suffered a couple of years back.
"But look, let's just wait and see. I don't want to dive in too quick, we'll wait and see what the examinations say but we're all fearing the worst."
Waghorn was ruled out for two months in 2016. Gerrard said Murphy's injury could keep the 28-year-old out of action for an extended period.
"Jamie's sad, he's upset, I think he's fearing the worst," Gerrard said. "We're devastated. That's the only downer for us today. We're going away on the back of a fantastic victory but it's come at a cost because Jamie looks like he'll be missing for quite a while. We'll get him checked out, we hope it's not as bad as we're first fearing.