Bayer Leverkusen rejected a bid from Espanyol before allowing Theofanis Gekas to join Portsmouth on loan.
Gekas has moved to Fratton Park for the rest of the season with a view to signing for Pompey on a permanent basis.
The Greek international was also wanted by Espanyol, but Bayer's sporting director Wolfgang Holzhauser has confirmed the offer was not up to scratch.
"Espanyol's bid for Theofanis Gekas was unacceptable," Holzhauser told Bild.
Holzhauser is now looking for a replacement for Gekas, but revealed Bayer will not be able to bring forward the signing of Eren Derdiyok, who is set to join from Basel at the end of the season.
He added: "We have spoken to FC Basel about Derdiyok, but they told us they need him in an attempt to win a place in the UEFA Champions League next season.
"That is about hard cash for Basel and we would only have been able to sign him now, if we put up big money. That was out of the question for us."
Nurnberg's Angelos Charisteas and Rangers' Kris Boyd have been linked with moves to Leverkusen before the transfer window closes.