Arsenal defender Gabriel was replaced in the Premier League in the 16th minute of the Premier League against Fulham Yawar.
The 27-year-old midfielder, after seeing pain in the spinal cord, before he rushed to replace Jacob Queur.
This is a dangerous blow to Mikel Arteta, who will travel to Everton in the Premier League on Saturday before hosting Real Madrid in the Champions League quarter-finals.
The Gunners has been in trouble with a hamstring injury this season, with Talisman Bukayo Saka returned to the squad for the game against Fulham after being missed for three months due to respiratory problems.
Kai Havertz and Gabriel Isa have also been rejected until the end of the campaign.
Gabriel has made 28 appearances in the Premier League this season, finishing second this season, scoring three goals, as well as a key member alongside William Saliba.