The 23-year-old arrived this week from Sporting in a deal worth £38million, which could rise to £42million with add-ons.
He adds the number eight link that Wolves were missing in midfield and Lage has backed him to prove his worth.
“He can be very important for us,” Lage said.
“You know what he did, especially in the last two years at Sporting. He can be an important player for us. The challenge was for him to come and compete in the Premier League. It’s so hard to play in.
“I think it will be good for him to play in the Premier League, it’s a big player for the Premier League.
“He is a box-to-box midfielder, he can drop near the centre-backs to build up, when he has space we can see what he can do, and he drives forward. In the final third he does the movements I like to go inside the box.
“He can give us these three parts to his game. It’s important to have a midfielder with these profile.”
Going in the opposite direction, Morgan Gibbs-White departed for Nottingham Forest for a deal worth up to £42.5million.
Although Lage wanted to keep the attacker, he hinted that his departure was due to the money offered, Gibbs-White’s reluctance to sign a new deal and the player’s desire to be reunited with Forest boss Steve Cooper.
“It’s about the financial situation,” Lage said. “We started the season with the ambition to create a different squad – the squad which went to Spain (for pre-season) and the squad today is completely different.
“I don’t want to see anyone unhappy. I enjoyed working with Morgan – he goes to Nottingham to work with the coach who worked with him at Swansea (on loan) and the national team (England’s Under-17 World Cup winners).
“In one or two years he can be one of the best young footballers to play in the Premier League.”
Gibbs-White’s big money move has made him Wolves’ most valuable academy graduate ever, as he creeps into the top 10 list for most expensive English players in history.
That pathway from the academy to the first team is crucial for Lage – as the head coach focuses on two youngsters who have impressed.
“It’s very important. You are talking to a guy who had a pathway in the Benfica academy,” Lage added. “If I show you a photo of my team in the under-15s, you can see where those players are. Ederson, Dias, Cancelo, Bernardo Silva, Helder Costa, Goncalo Guedes.
“It’s not just about Morgan, it’s about Max and Luke. Also Connor, who is with us. Also, one of the kids that is with us and surprised me since January is Chem (Campbell). He has grown up as a player and man and is doing very good things in training.
“What I did at Benfica is what the club is doing here. A good pathway for them to grow up and then they start training with the first team.
“After, they can play and be squad players. If they don’t have space here, they can go on-loan to grow up. After that experience, they can have a position in the first team.
“The academy does a great job. I am happy with what Chem is doing and also (Hugo) Bueno. We have two or three good kids and we can see the potential they have.”