Arsenal Gabriel defender was replaced in the 16th minute of his Premier League match at home against Fulham after his injury.
The 27 -year -old Brazilian back fell after his appearance to hurt the knee strings, before he wandered to replace Jacob Kyoror.
It is a possible blow to the Mikel Arteta team, which travels to Everton in the Premier League on Saturday, before hosting Real Madrid in the quarter -finals match in the quarter -finals on Tuesday.
Gunners was exposed to injury problems this season, as Talisman Bukayo Saka returned to the team for the match against Fulham after he lost three months with a problem in the knee strings.
The attackers Kai Hafertz and Gabriel Jesus were excluded until the end of the campaign.
Gabriel played 28 games in the English Premier League for Arsenal second place this season, where he scored three goals, and a main member in their back line alongside William Saliba.
