He said they are "a little bit limited" in who can play because of Spurs' long injury list, with Frank saying there are only 11 first-team players available.
Xavi Simons "has a swollen ankle" and he didn't train on Monday, but he will "play through pain" because of a lack of other options. Frank added: "We have three players that need to push massively to get through 90 minutes."
On whether discussions with the board have taken place over his position: "There is a backing and support. I had lunch with them today and it is all good. It's part of the media circus."
The Dane said the players need the support on Tuesday against "a very good German side" because "if we keep the support then magic can happen".
More from Frank on fans not backing him: "It's not about me, it's about supporting the team and supporting the players. I am happy to take the blame as long as everyone supports the players. If your back is against the wall then you fight and that is what I do. It's not about me, we need to win football matches and we need to win together."
He said his best players "haven't been available enough" this season so it has been "more difficult, but we still need to find a way" to get results.
On what they are doing: "There's a lot of signs that it's going the right way. We are much closer than we think so we just need to keep going."
Frank confirmed Dominic Solanke is part of the Champions League named squad and Mathys Tel has been withdrawn. On dropping Tel and how supporters will take it, he said: "I do not know. I hope people understand that it is not a straightforward decision. It is him or Dom [Solanke] in the team tomorrow. That is the decision. I believe it is the right one and that is what I went with."