Bayern Munich midfielder Joshua Kimmich is not guaranteed to face Arsenal in Wednesday's Champions League clash, assistant coach Aaron Danks has admitted.

The long-serving midfielder had been earmarked as a shoo-in for the Bayern XI at the Allianz Arena, but he was unexpectedly missing from the Bavarians' training session on Tuesday.

Kimmich's absence sparked surprise given that the 31-year-old has been an ever-present for Vincent Kompany's side this season, making 10 appearances in all competitions, nine from the first whistle.

Kimmich captained Bayern to a 6-1 victory over RB Leipzig at the weekend in the absence of skipper Manuel Neuer, seeing out the full 90 at the Allianz Arena.

However, speaking to the media in his pre-game press conference, Danks revealed that the Germany international missed practice owing to personal reasons and is a doubt for Wednesday.

Why Joshua Kimmich missed Bayern Munich training before Arsenal match

"Josh was absent today for personal reasons. I’m not sure what that will mean for tomorrow," Danks said, before also delivering the latest on legendary goalkeeper Neuer.

The 40-year-old sat out the weekend's thumping of Leipzig with a foot injury, but he was back in training on Tuesday ahead of an expected return to shot-stopping duty against Arsenal.

Danks remained coy in his press conference, though, adding: "We haven’t made a decision yet. Manu’s been back on the pitch for two days, which is brilliant. We’ll decide together with the coaching staff and Vincent. But it’s great to have Manu back."

Danks fielded questions from reporters in Kompany's place due to the Bayern boss contracting an illness, and it is possible that the former Manchester City defender will not be barking orders from the touchline on Wednesday.

"Vincent has a viral infection," Danks added. "It’s important that he gets some rest. We’re monitoring the situation constantly and will see how he’s doing tomorrow. We’re in constant contact. He’s giving us his input; as for whether he’ll be able to be at the Allianz Arena tomorrow, we’ll see tomorrow."

Bayern are already missing the suspended Michael Olise for the visit of Arsenal after the Frenchman's red card in the 3-3 draw with Viking FK, while Jamal Musiala is nursing a thigh injury.

How could Bayern Munich replace Joshua Kimmich against Arsenal?

Should Kimmich miss out for Bayern against the Premier League champions, Kompany has one obvious midfield replacement, and two wildcard candidates.

Aleksandar Pavlovic is expected to operate as one half of the double pivot regardless, and the 22-year-old would likely be joined by 21-year-old Tom Bischof in a Kimmich-less XI.

Bischof completed the full 90 of last week's 3-3 draw with Bayern, but he has only made one Bundesliga start this season, coming off the bench in a further five top-flight games.

Alternatively, Kompany could shift right-back Konrad Laimer into a formerly familiar midfield role, which the Austrian largely played for RB Leipzig and Red Bull Salzburg, thereby allowing Josip Stanisic or Sacha Boey to operate in defence.

Finally, the hosts could hand a shock Champions League debut to 18-year-old Senegalese starlet Bara Sapoko Ndiaye - signed from Gambinos Stars this summer - but a Pavlovic-Bischof midfield is the first option if Kimmich is forced to miss out.