The former Camp Nou goalkeeper praised the outgoing Barca No.1 for totally understanding what it takes to thrive with the Catalans but has hope for the young German
Ter Stegen's move from Borussia Monchengladbach has yet to be made official but has been agreed upon, while Valdes confirmed over a year ago that he will leave Catalunya when his contract expires this summer.
Baia, who spent two seasons at Camp Nou before returning to Porto in 1998 after falling out of favour under coach Louis van Gaal, thinks Valdes' high standards will be hard to match, but advised Ter Stegen to stay calm in the face of what will no doubt be intense pressure.
"I've seen little of Ter-Stegen," the former shot-stopper said to La Xarxa. "He is a young, fast goalkeeper, who does his role well, but I have not yet sufficient data to make a proper analysis.
"But he is young and has quality, and last year had a great season with Borussia Monchengladbach.
"My advice to Ter Stegen would be to arrive quietly. He'll know how to control the pressure of the environment and to play in a natural and calm way. If you are quiet, you will reach a high level naturally."
However, Baia can still not get his head around why Valdes would decide to leave Barcelona at the peak of his powers.
"Valdes played an excellent game against Manchester City in midweek, making a super save at a very important moment," he pointed out.
"The truth is that he is having an excellent season at a very high level and from a distance I do not understand why he will not renew his contract with the club. It's hard for me to understand, but this is football.
"He's a good goalkeeper, the best in Europe. He's won major titles in the end, which is what counts for one's career, and he has also shown tremendous consistency, which is the most important feature that a goalkeeper should have.
"Valdes is a very important player for the club and even more in the culture of an attack-minded club like Barcelona.
"There's nothing better than a goalkeeper who knows the culture, knows he has to play a little more advanced, knows he has to play well with his feet, and this what Valdes makes perfect for Barca."