METAIRIE, La. -- The New Orleans Saints' top two quarterbacks -- Taysom Hill and Trevor Siemian -- both landed on the reserve/COVID-19 list on Thursday, along with safety Malcolm Jenkins and six other backup players.
Hill and Siemian have both tested positive for COVID-19, sources told ESPN's Adam Schefter.
The other six players added to the list Thursday were offensive tackle Jordan Mills, guard James Carpenter, linebacker Kaden Elliss, safety Jeff Heath, defensive end Jalyn Holmes and defensive tackle Christian Ringo.
The Saints (7-7) have also been without coach Sean Payton since Friday because of a positive COVID-19 test, and they placed tight ends Adam Trautman and Juwan Johnson on the COVID-19 list earlier this week as well.
Interim head coach Dennis Allen decided to cancel a scheduled walk-through practice on Thursday to keep everybody distanced and all meetings were held virtually. The Saints did put out an estimated injury report, however, listing starting offensive tackles Terron Armstead and Ryan Ramczyk as not participating with knee injuries.
If Armstead and Ramczyk both remain sidelined, that would make Mills' absence even more costly -- and it would significantly increase the degree of difficulty for Book.
Book has not tested positive, sources told ESPN, but the Saints will likely have to add depth since he is the only healthy quarterback on the roster or practice squad. Running back Alvin Kamara has been designated as the Saints' emergency quarterback in the past.
Book, who was drafted in the fourth round out of Notre Dame, would be the fifth quarterback to start for the Saints during the 2021 calendar year. Drew Brees retired after making two playoff starts in January and Jameis Winston suffered a season-ending ACL tear in Week 8 before Siemian and Hill took turns replacing him.
As a result of that attrition, the Saints rank an uncharacteristic 30th in the NFL this season with 194.6 passing yards per game and last with a completion percentage of 57.4.
Saints offensive coordinator Pete Carmichael Jr., who has taken over play-calling duties in Payton's absence, said all of New Orleans' quarterbacks have remained part of the virtual process to prepare them all based on who is available and to "have some flexibility."
If it is Book, Carmichael said, "we know he'll be prepared."
"Just going back to the pre-draft days, there were a lot of things we really liked," Carmichael said. "He's smart, he had a very productive career, he's accurate, he's mobile, he's able to process information in meetings. So he's been real sharp in meetings. And we've been impressed with what he's done on the field maybe with the practice squad. So we feel really confident in him as a player.
"He's a very confident kid, and one thing we know about him is he has a strong passion for this game, he loves to play. He's a competitor, he wants to be out there. So I think those things will suit him well."
Book, 23, went 30-5 as a starter at Notre Dame, finishing with the most wins in school history. He went lower in the draft, in part because he is just 6 feet tall. But his mobility and ability to make plays when the pocket breaks down were among his calling cards at Notre Dame.
This will be the latest hurdle for a Saints team that has dealt with a barrage of significant injuries, a hurricane displacement to Texas for the first month of the season and now a handful of COVID-19 issues. They were missing a large part of their assistant coaching staff in a Week 2 loss at the Carolina Panthers because of a COVID-19 outbreak.
The Saints were on the other end of an infamous game last year when COVID-19 protocols wiped out the Denver Broncos' entire quarterback room. The Saints beat the Broncos 31-3 while Denver used a combination of practice squad wide receiver Kendall Hinton at quarterback and direct snaps to running backs.