Can missed the 4-1 Premier League win over Stoke City at the weekend due to suspension, but is expected to return to the starting XI for the second leg of the quarter-final tie with Dortmund.
Liverpool recorded a 1-1 draw in the first leg at Signal Iduna Park and will be looking to book their ticket for the semi-finals at Anfield.
"Emre has had the rest at the weekend, unfortunately missing the game. But it was good to get a result without him," Milner told Liverpool's official website.
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"He has been brilliant this year in midfield, brilliant on the ball and his energy, strength and pace winning the ball back for us is massive. He'll be a big plus for us coming back.
"Whatever team the manager decides to play, I'm sure the lads will be ready and I'm sure Emre will want to get one over a few of his Germany team-mates as well."
Can's absence versus Stoke saw Joe Allen make his way into the starting XI and Milner was equally full of praise for the Wales international.
"Joe's a top player, with a great attitude as well. He probably hasn't played as much as he would have liked over the last couple of months," Milner added.
"To come in and hit that level straight away, and the intensity he has played with, is unbelievable. He's great on the ball and [with] his energy levels.
"He's a top player and a big player for us. He's a great lad as well, so I'm delighted for him to come in and play really well. Everyone knows what a top player he is."