Ramsey has not featured since coming off at West Ham on Boxing Day because of a thigh problem.
Wenger confirmed after Tuesday's 2-2 home draw against Swansea that the Wales international had suffered a "little setback" in his rehabilitation.
Ramsey had been pencilled in for a return in Saturday's Premier League game against Manchester City, but his comeback has now been put on hold.
Wenger said: "Ramsey is progressing well, but we need to be patient for a few more weeks."
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