The 22-year-old German defender was wanted at Newcastle, but he rejected a move away from Freiburg in the winter transfer window.
Newcastle are expected to try and sign him again in the summer if they manage to survive in the Premier League this season, with Schlotterbeck a highly rated defensive talent.
Schlotterbeck is also wanted by the biggest clubs in Germany, with both Bayern Munich and Borussia Dortmund believed to be interested in getting their hands on the young defender.
Saier stressed that it is no surprise that big clubs are interested in the defender as he is a special player who is only going to get better in the coming years.
He conceded that Freiburg have to remain open to the possibility of Schlotterbeck leaving the club at the end of the season.
The Freiburg deal-maker told German magazine Kicker: “Nico is a special player who has a lot of potential for development.
“The combination leads to interest from big clubs.
“That’s why we will have to deal with his personal details in the summer with an open mind.”
Schlotterbeck has featured 52 times in the Bundesliga and has already broken into the Germany squad.
