The team made the official announcement on Saturday, after establishing the possibility on Friday.
"We're proceeding as if I won't coach on Sunday," Saleh said Friday on a Zoom call with reporters. "If I do come up with two negatives, it would be an easy adjustment. But we're operating as if I will not be there Sunday."
Saleh, who said he feels "good," was awaiting a test result from Friday morning. He would have to test negative again Saturday to clear league protocols.
Tight ends coach Ron Middleton, a former NFL player and longtime assistant who hasn't been a head coach on any level, is poised to step in after being named the interim coach Wednesday.
The Jets (3-11), mired in their third three-game losing streak, have been dealing with a COVID-19 outbreak. They have 16 players on the reserve/COVID-19 list after activating wide receiver Jeff Smith and special teamer Justin Hardee on Friday.
Saleh expressed a hint of gallows humor, saying, "The whole season has been filled with adversity. Why not finish it with a little bit more?"
The Jets are not anticipating any further activations before Sunday, which means they will be down six starters, including four on defense, because of the coronavirus.
Both safeties, Ashtyn Davis (COVID-19) and Elijah Riley (concussion), are out, all but fully depleting the position. The Jets' options at safety are rookie Jason Pinnock, a converted cornerback, and two veteran newcomers, Will Parks and Kai Nacua, who joined the team this week.
Saleh sidestepped a question on whether he believed the game should be postponed, saying, "It's not my decision to make."
Quarantining in a hotel, Saleh has been involved in virtual meetings. He reached out to Cleveland Browns coach Kevin Stefanski, who had to miss a game because of COVID-19. Saleh said Stefanski told him he would be "fine" during the week because everything is virtual, but not so fine on game day.
"He said Sunday is going to be miserable," Saleh said. "So I'm looking for misery."
Saleh said four of his seven children have tested positive but are symptom-free.
The decision to elevate Middleton caught some by surprise, but Saleh explained the decision by saying Middleton is an experienced and well-respected coach on the staff. Saleh also didn't want to disrupt one of his coordinators by giving them an expanded role.
Middleton, 56, who had head-coaching aspirations early in his career, said he is looking forward to the opportunity. He will meet virtually on Saturday with Saleh and the staff to discuss the game plan and how he should manage the game.
"It's been a smooth operation, man," Middleton said. "It's kind of scary, with everything that's going on and whatnot and all the uncertainty, but people are just going about their business."
The outbreak, coupled with injuries, could affect rookie quarterback Zach Wilson. If Jamison Crowder (calf) doesn't play -- he's a game-time decision -- Wilson won't have his top three wide receivers because of injuries. Starting tight end Ryan Griffin (knee) was placed on injured reserve this week, and the starting guards, Alijah Vera-Tucker and Laurent Duvernay-Tardif, are on the reserve/COVID-19 list.
Despite the lineup upheaval, Wilson, the No. 2 overall pick this year, is in "a great place mentally," Saleh said.
Though it's not reflected on the stat sheet, the team believes Wilson has improved in recent weeks. Saleh said Wilson has been playing "free" and relaxed. Previously, he was so concerned about playing within the structure of the offense that it would "lock him up. ... He would get stuck," Saleh said.