on the sidelines

1. Observing rather than taking part, out of the action, as in Bolivia's neighbors remained on the sidelines, waiting to see which faction in the dispute would prevail. This idiom comes from sports. The sidelines are the two lines defining the sides of the court or playing field and the area immediately beyond them where, in such sports as football, the non-playing team members sit. [First half of 1900s]

Example Sentences

It was injuries that derailed their title challenge in 2024-25, with Odegaard himself having a spell on the sidelines with an ankle problem.

From BBC

The court’s conservative majority asserted that Wilcox must remain on the sidelines for now because “the Government faces greater risk of harm from ... allowing a removed officer to continue exercising the executive power than a wrongfully removed officer faces from being unable to perform her statutory duty.”

From Los Angeles Times

Eight years earlier, at the climax of a season that included suspension, tabloid headlines and “the Las Vegas freeway incident,” he blew a chance at redemption, when, after a game-losing mistake, he punched a fan on the sidelines, who crashed into his son, a sick child in a wheelchair.

From Los Angeles Times

Talks between the three countries and Iran on the sidelines of the UN General Assembly earlier this week failed to produce a deal which would have delayed the sanctions being reimposed.

From BBC

In Season 2, this cold and calculating man in a business suit stays on the sidelines of the Jack of Hearts prison game by picking a submissive and compliant partner, but by the end teams up with Banda.

From Salon