Celtic manager Neil Lennon admits to holding an interest in Sebastian Boenisch and Aidan White, but says no deals have been done.
The Hoops are preparing themselves for a season they hope will bring domestic success and continental progress in the UEFA Champions League.
Competing on multiple fronts will require strength in depth, meaning fresh faces will have to be added to the Parkhead ranks.
Lennon insists he is in no rush to bring extra bodies on board, but he continues to search out potential new recruits.
Polish full-back Boenisch, who has just left German outfit Werder Bremen, and former Leeds defender White are among those currently under consideration.
"We've been in touch with Sebastian's representatives but that's as far as it's gone," Lennon said in the Daily Record.
"Aidan interests us but nothing's near to happening there. I'm going with what I've got at the moment."
Meanwhile, Celtic full-back Emilio Izaguirre has played down claims that he is ready to quit football and turn his attention to a political career in his native Honduras.
He said: "The party (National Party of Honduras) only asked me for a picture to support them.
"I've no interest in politics. I live for football. My only interest is in getting ready for the new season with Celtic."