Germany left back Dennis Aogo joined Schalke on loan from Bundesliga rival Hamburger SV on Thursday.
Schalke said the 26-year-old Aogo signed a contract through June 2014.
''Dennis is a player who will certainly help us with his versatility. He gives us additional options in our squad,'' said Schalke general manager Horst Heldt.
Heldt said Wednesday that Schalke had secured an option to make the loan deal permanent at the end of the season.
Schalke had been in the market for a left-sided player following the departure of Michel Bastos, who was on loan from French side Lyon, to United Arab Emirates club Al Ain.
Aogo can play on the left of defense or midfield, and is likely to make his Schalke debut on Saturday against Bayer Leverkusen as regular defenders Benedikt Hoewedes and Christian Fuchs are both suspended.
''Schalke are a big footballing challenge, not least because of the matches in the Champions League. I'll do all I can to help the team,'' Aogo said.
Aogo made 133 Bundesliga appearances for Hamburg after joining from Freiburg in 2008.
He has made 12 appearances for Germany.
