Stoke chairman Peter Coates told BBC Radio Stoke: "He's a player that we're interested in, but I can't tell you how talks are going.
"He'd give us good cover, in fact he could play, he'd be good competition for a defensive place in the team."
Coates added: "We're talking to him to see if a deal can be done. He would be very useful for us, he's a good player."
Upson began his career at Luton Town, before a £2m move to Arsenal in 1997.
He failed to make an impression at the Premier League club however, and after loan spells at Crystal Palace, Reading and Nottingham Forest, signed for Birmingham in 2003.
The Suffolk-born defender made 112 league starts for Blues,before a £6m switch in 2007 to Upton Park, where he went on to make 145 appearances.
Source: BBC Sport
Source: BBC Sport