Schalke sign Karimi on short-term deal
The 32-year-old Karimi, who has won 112 international caps and once had a two-year spell at Bayern Munich, joins from Iran's Steel Azin Teheran FC.
Schalke coach Felix Magath was in charge of Bayern when the 2004 Asian Footballer of the Year played for the Bavarian club. Karimi also played in the 2006 World Cup in Germany.
Charisteas, 30, without a club since leaving French top-flight strugglers Arles-Avignon in November, will boost an impressive Schalke front-line that already includes Spaniard Raul and Dutch striker Klaas-Jan Huntelaar.
The Greek, who has also played for Ajax Amsterdam, Werder Bremen and Bayer Leverkusen, scored the winner in his country's surprise Euro 2004 final victory over Portugal.