Cleethorpes-born Wrack, who was 27 on Monday, has made over 200 appearances for the Saddlers in his 5 years there, scoring over 30 goals.
He began his career as a trainee at Derby, before moving to home-town club Grimsby in a £100,000 deal in 1996. He made only 5 starts there, however, before joining Walsall two years later on a free transfer.
Meanwhile, Grimsby's 33-year-old right-back John McDermott is another name being linked with City.