No. 9 Wisconsin might be down to its fourth-string quarterback after Chase Wolf tested positive for COVID-19, the Milwaukee Journal Sentinel reported Monday night.

Wolf, the Badgers' third-stringer, was not at Monday's practice after he tested positive for the virus, according to the report. The Journal Sentinel and Wisconsin State Journal both reported Sunday that Graham Mertz, who started the season opener Friday, tested positive over the weekend.

Wisconsin was awaiting the result of a polymerase chain reaction (PCR) test to confirm Mertz's result or rule it a false positive. Wolf also will take a PCR test to confirm a positive result from the antigen test. If confirmed, both Mertz and Wolf would miss a minimum of 21 days, according to Big Ten COVID-19 protocols for players.

Wisconsin is already without starting quarterback Jack Coan, who suffered a foot injury in preseason practice and underwent surgery Oct. 6. Coan, who started 18 games for the Badgers the past two seasons, is out indefinitely.

Wisconsin coach Paul Chryst, speaking with reporters Monday before practice, would not address Mertz's status or that of any player regarding COVID-19 testing. Chryst said he is confident that Wisconsin can play this week's game at Nebraska (0-1).

Redshirt junior Danny Vanden Boom likely would be the next quarterback in line if both Mertz and Wolf are out. After Nebraska, Wisconsin hosts Purdue before visiting No. 13 Michigan. Vanden Boom appeared in three games in 2018, completing the only pass he attempted for a 3-yard touchdown.

Chryst said he has no issue with the Big Ten's 21-day policy, which is more stringent than those of other leagues.

"The No. 1 concern for the league, and I appreciate this, was how do we best keep everyone as safe as possible regarding the virus, and then how do you manage the impacts of it when someone has it,'' Chryst said. "Admittedly, they told us it was more conservative, and if that helps one person, then that's a good thing for us. We've known that there was a lot of work that went through this. For us to play, if that is something that's in the best interest of everyone involved, then I completely support it.''

In a statement issued Sunday night, Wisconsin said it "will not be releasing COVID-related testing information regarding any individual student-athlete, due to medical privacy."

The statement noted that no player who participated in Friday's game tested positive before the game or reported any symptoms.

"Wisconsin Athletics continues to conduct daily antigen testing for the student-athletes, coaches and selected support staff associated with the Badger football program," the statement read. "Individuals who receive a negative antigen test result continue to participate in team activities. Individuals who receive a presumptive positive antigen test result are removed from team activities and are required to take a PCR test to confirm positivity."

Mertz, a redshirt freshman, was nearly flawless Friday in a 45-7 win over Illinois. He completed 20 of 21 passes for 248 yards and five touchdowns. He set team records for single-game completion percentage (95.2) and touchdown passes. Mertz completed his first 17 pass attempts, matching a team record for consecutive completions.

A native of Overland Park, Kansas, Mertz is considered the top quarterback recruit in Wisconsin history. ESPN rated him as the top pocket passer and No. 21 overall player in the 2019 recruiting class.