Frank admits he sees Bergvall as a midfield "No8", though insists he is capable of playing as a "No10".
“I think Lucas is very talented. I think he will end as what we call an eight, in my opinion, that’s where I think he will end, but who knows?,” Frank said ahead of Sunday's clash with Crystal Palace.
“I think he’s more than capable of playing as a No10, for example, or he can play a more midfield role from the side as he did against Liverpool.
“I think he’s a player we can use in different roles, which I think is hugely beneficial and hugely important, to have that player who can run in behind, he’s very good at pressing, he’s good on the ball, he can drive forward with the ball.
“You need different types. For example, against Liverpool, they came with five midfielders, so he (Szoboszlai) moved in ahead of the extra midfielder.
“The way he defended for the first 30 minutes was a big reason why I felt we were slightly on top in those 30 minutes. I think it’s a big reason for that, instead of playing with two main wingers.
“To have a player like him who can be that flexible is very important.”
Frank added, “Over time he will fall into a more fixed position. t’s completely normal for a young player to play in different positions.”