The Spaniard was substituted after pulling up 71 minutes into the game at Loftus Road, which the Merseyside club won thanks to Daniel Agger's header and a Luis Suarez double.
And Pascoe, who led the team in the absence of the ill Brendan Rodgers, has now conceded that Liverpool may be without the full-back for some time.
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"He was terrific today, absolutely superb, and the way he's been performing these last couple of months has been a joy to watch.
"It's a shame, and hopefully he's not out for too long."
The 26-year-old has appeared in 12 Premier Leagues so far this season.