Former Sunderland and Hearts goalkeeper Gordon is without a club and has been training with the Light Blues.
Boss Ally McCoist is keen to strengthen the position after confirming Neil Alexander is unlikely to remain with the Third Division champions next season.
Asked for his thoughts on Gordon, Foster said: “He’s an international goalkeeper.
“Everyone agrees that, when he’s fit and playing, he would be in the Scotland set-up.
“Signing someone like that would be massive.”
Foster agreed a two-year deal with Rangers following his release from Bristol City and will complete his move on September 1 when the club’s transfer embargo is lifted.
SUNDERLAND FIXTURES:
Saturday August 17 15:00Premier League Sunderland v Fulham Saturday August 24 15:00Premier League Southampton v Sunderland Saturday August 31 15:00Premier League Crystal Palace v Sunderland Saturday September 14 15:00Premier League Sunderland v Arsenal Saturday September 21 15:00Premier League West Brom v Sunderland Saturday September 28 15:00Premier League Sunderland v Liverpool Saturday October 5 15:00Premier League Sunderland v Man Utd Saturday October 19 15:00Premier League Swansea City v Sunderland Saturday October 26 15:00Premier League Sunderland v Newcastle United
Source: Sunderland-Mad
Source: FOOTYMAD
