Bukayo Saka was forced off injured for Arsenal early on in their Premier League game against Crystal Palace on Saturday.
The England winger, 23, held his hamstring after attempting a cross before going down and being substituted in the 25th minute.
Arsenal were leading 2-1 when Saka was replaced by Leandro Trossard.
Saka, Arsenal's main attacking threat with 15 goal contributions in 15 league games, was sidelined earlier this season with a hamstring injury. He withdrew from the England squad in October before missing two Arsenal games, including a 2-0 defeat at Bournemouth.