It was nearly five years ago, in December 2014, when Arsène Wenger, with that concerned, patrician demeanor of his, first voiced in public his fear that Alexis Sánchez was running the risk of burnout.

Sánchez, a forward, had arrived at Arsenal the previous summer, on the back of not only a demanding season for Barcelona but a draining World Cup: Sánchez had shone as the star of Jorge Sampaoli’s all-action Chile team in Brazil.

He had taken to the Premier League quickly, but Wenger, his manager, worried that his competitive streak, his refusal to countenance the idea of a break and a rest, might come to trouble him. Sánchez, nearing his 26th birthday at the time, was playing in “the red zone,” Wenger said, thanks to his commitments for both club and country.

“Unfortunately,” Wenger said, “you never know how far you can push it.”

In the years that followed, Wenger would issue the same warning half a dozen times. They all went unheeded. Not only did Sánchez refuse to consider the idea of sitting out a game for Arsenal, he never ignored a call from his nation. He came to exist, almost exclusively, in the red zone: winning the Copa América on home soil in 2015, and then again in a special edition in the United States the next summer.