Celtic have expressed interest in Timo Hildebrand and Stipe Pletikosa as they look to solve their goalkeeper shortage.
The Hoops have been left with limited options between the sticks after Polish keeper Artur Boruc departed for Fiorentina this summer, while England shot-stopper David James has recently postponed transfer talks at Parkhead following interest from Bristol City.
Former Germany keeper Timo Hildebrand is currently a free agent after being released by Bundesliga club Hoffenheim at the end of last season.
And the former Stuttgart and Valencia shot-stopper is hoping to ply his trade with the Bhoys in the SPL this term.
"The interest of Celtic in my services is a fact," Hildebrand told BILD. "This is flattering to me, it is an ambitious club.
"I am preparing myself for the new season with regular individual training at this point in time and I would be ready to take the challenge of playing for that club."
Another Celtic target is Croatia international Pletikosa, who the Bhoys are reportedly interested in signing on a season-long loan.
Spartak Moscow No.1 Pletikosa was approached by the Hoops in 2005, but negotiations fell through when Gordon Strachan opted to sign Boruc instead.
Tottenham have also made a bid for the keeper, but he is reluctant to take a back seat to Heurelho Gomes and Carlo Cudicini, and is instead eyeing a switch to Parkhead.
"Before Boruc signed, I got an offer to go to Parkhead but it fell through," Pletikosa told the Daily Record.
"I was disappointed as I'd love to play there. I know a lot about the club and its history."