Richards is expected to complete his prolonged £8 million switch to Spurs on Friday and Gray is hoping to use some of that money to bring Upson to St Mary's.
The highly rated star joined Arsenal from Luton Town for £2 million in 1997 but has found it difficult to break-up the long running partnership of Tony Adams and Martin Keown in the heart of the Gunners defence.
The arrival of Sol Campbell this season has pushed Upson further down the pecking order at Highbury and he only made his first appearance of the season as substitute in Wednesday's 3-2 win over Schalke in the Champions League.
Upson spent two loan spells at Crystal Palace and Nottingham Forest last season and he could find it even harder to break into the Highbury first team after the arrival of Greek defender Stathis Tavlaridis this week
The England Under-21 international, who would probably cost in the region of £3 million, has failed to establish himself as a first time regular and could be keen on a move away for regular action.
Gray also has Leeds United defender Michael Duberry, Birmingham's Darren Purse on his list of possible replacements for Richards, but Upson is his number one target.
