Spector has signed a new two-year contract at St Andrew's after making 29 league appearances for the Blues last season, and Clark is pleased to secure the USA international's services until 2015.
The 40-year-old told the club's official website: "His versatility is a big thing for us as he can cover different positions.
"As well as midfield, he can play as a full-back, although I ultimately think that as he goes on he could be a decent centre-half because he's an aggressive player, he's got good aerial ability and he's mobile.
"In terms of football, he's still young, but he's a very experienced player in terms of the games he's had for a player of his age."
Spector joined Birmingham from West Ham United in 2011.