In the 12 league games this season, Sa and Wolves have conceded 12 goals, keeping two clean sheets in the same time process.
Prior to Wolves' Premier League visit to Norwich City tomorrow afternoon (3pm kick-off), Lage was faced with the question on Sa's form so far at Wolves.
"I'm not too much impressed because I know Jose since he was 17," the 45-year-old said.
"I never worked with him but he worked with the Benfica academy. When I knew that Rui Patricio went to Roma and they started about Sa, he's a good goalkeeper and I think it (Wolves) was the right place to come."
John Ruddy works alongside Sa as his back-up and Wolves' cup choice in between the sticks, but Tony Roberts - who also works with the Wales national squad - arrived at the club in the summer as goalkeeper coach.
Lage worked with Roberts whilst he was at Swansea City in 2017 and heaped praise on the goalkeeper coach so far this season.
"I think also, because I cannot put him aside of Jose's success, the way John (Ruddy) works every day and the way Tony works with the goalkeepers.
"Tony is one of the best goalkeeper coaches I know because he will go to the little details, that's why I was so impressed when I worked with at Swansea," Lage continued.
"I put in my mind, maybe one day if I get my chance and to come here, I will invite Tony to work because, for me, he's one of the best, a good person, a top man and he's one of the best people to go into every detail."