The defender recently got back from a long-term injury and immediately got into the team following an injury crisis in the right-back position.
With Arsenal pushing for the Premier League title and having just two games left, the England international was supposed to fill in at the right back position.
However, the 28-year-old sustained suspected medial collateral ligament damage to his right knee during the first half of Arsenal's 1-0 victory over West Ham on Sunday.
White ruled out of the season
Following the match, manager Mikel Arteta expressed concern, stating, "He doesn't look good at all."
White's injury creates a defensive crisis for the Gunners at a crucial time, with fellow right-back Timber also unavailable.
The club is facing a pivotal few weeks as they chase their first league title in 22 years and prepare for the Champions League final against Paris Saint-Germain on May 30.
This season has been another challenging one for White, who has been hampered by recurring fitness issues over the past 18 months.
He previously missed three months of football in the 2024-25 season after undergoing knee surgery.
This term, he has made 30 appearances across all competitions but has only started nine league games, stepping in recently to cover for the injured Timber.
Arsenal's campaign concludes with a home fixture against Burnley on May 18, followed by a trip to Crystal Palace on the final day, May 24, before their European showdown in Paris.