Devin Williams’ touted Airbender changeup has been the baseball equivalent of an air ball.

The struggling closer, still trying to get his sea legs in his first season as the Yankees’ closer, was viciously booed off the mound Friday night after failing to protect a one-run lead (and failing to record an out).

Toronto scored three runs in the inning and sent the Yankees to a dispiriting 4-2 loss in front of an irked sellout crowd of 46,081 at the Stadium.

Many of those fans, after booing Williams, loudly chanted “We want Weaver!” — referencing popular reliever Luke Weaver, who has not allowed a run this season and who successfully took over closer duties from Clay Holmes last season.

After Friday’s implosion, Aaron Boone didn’t guarantee that Williams will remain in the job. “We’ll see,” Boone said of perhaps moving him to some lower-leverage situations to get on track. “We’ll kind of talk through that stuff. We want to do everything we can to get him right because we know how good he is.”

It was Williams’ first blown save, which hardly tells the story of what has been a forgettable first month as a Yankee. After he was charged with three runs Friday, his ERA soared to 11.25 in 10 games. He has allowed 12 runs (10 earned), 12 hits and seven walks in eight innings.

“I mean, truthfully, I don’t know,” he said of his command issues. “It’s something I’ve been battling for most of the season. It’s getting pretty frustrating . . . Nothing’s working right now.”

After the Yankees (15-11) manufactured a run in the bottom of the eighth — getting a hustle double by Cody Bellinger, who scored on a sacrifice fly by Austin Wells — for a 2-1 lead, Williams gave it away.

The righthander, the centerpiece of the Nestor Cortes deal with the Brewers in the offseason, had not pitched since April 19 in Tampa, when — in a non-save situation — he surrendered a four-run lead in the ninth inning of a 10-8, 10-inning loss.

Williams allowed a leadoff single by George Springer, one of the few Blue Jays off to a good start at the plate (Toronto went 9-for-90 in its recent three-game sweep at the hands of the Astros) and fell behind Andres Gimenez 2-and-0, causing a palpable dread to spread through the crowd. It was back on his side after two strikes, but he then hit Gimenez, putting two on with none out.

Alejandro Kirk, who has made a career of hitting Yankees pitching hard, drove a 1-and-0 changeup over Trent Grisham’s head in center for a two-run double that made it 3-2. In came righty Mark Leiter Jr. and Addison Barger scorched an RBI single to left to make it 4-2.

“I wish there was an easy answer,” Williams said. “It’s not a good feeling not to be able to get the job done for the team. They put us in a great position to win there and I couldn’t get it done today.”

In the bottom of the ninth, righthander Jeff Hoffman got Grisham to ground to first and struck out Aaron Judge swinging. Ben Rice doubled into the rightfield corner, but Paul Goldschmidt popped to second to end it.

The Yankees went 1-for-9 with runners in scoring position and stranded 11.

The Yankees received a terrific start from righthander Carlos Carrasco, who allowed three hits and two walks in five scoreless innings. He was pulled after only 67 pitches as Boone elected to start the sixth with lefty Tim Hill to face Vladimir Guerrero Jr. He promptly homered to give Toronto a 1-0 lead.

Toronto righthander Jose Berrios also was outstanding, allowing five hits and two walks in 5 1⁄3 scoreless innings.

The Yankees tied it in the seventh when Anthony Volpe doubled and scored on Oswaldo Cabrera’s single. After the Yankees went ahead in the eighth, Williams’ night quickly came apart, though the three-time All-Star still has the confidence of his teammates.

“I just told him, you’re the guy every time,” Jazz Chisholm Jr. said. “This is who we want to give it to and this is why you’re here. We all believe in you. We all have your back.”

DJ LeMahieu, who started the season on the injured list with a left calf strain, started a rehab assignment Wednesday with Double-A Somerset, going 3-for-3 with a home run, and played with Somerset again on Thursday. “So far so good,” LeMahieu said in the clubhouse Friday. “No pain.” LeMahieu, who does not have a set number of rehab games, is slated to play with Somerset again on Saturday and Sunday.