Myles Garrett’s knee injury will require surgery.

Coach Sean McVay said Monday that the Rams’ season-opening loss made it clear Garrett could not keep playing.

Garrett had no tackles or sacks in the Rams’ 27-7 loss to the San Francisco 49ers in Melbourne, Australia.

He played 61.5% of the defensive snaps.

McVay said the team had thought Garrett could work through the knee issue.

But after seeing him in a real game, McVay said, “maybe that’s not the case.”

Garrett is on injured reserve and will miss at least four games.

McVay had no updated timeline beyond that, pending the procedure’s results.

Garrett missed much of training camp with what was described as knee swelling.

McVay has not explained the exact injury.

The Rams traded for Garrett from the Cleveland Browns in June, sending pass rusher Jared Verse and three draft picks.

Before the game, Garrett said he felt “ready” and set goals of winning the Super Bowl and repeating as AP Defensive Player of the Year.

McVay said Garrett’s absence will not affect when Aaron Donald returns.

Donald did not travel to Australia as he works back into shape after two seasons out of football.

McVay said it is too early to know if Donald will play in the Rams’ home opener against the New York Giants next Monday.