The England international has been excluded from the club's pre-season plans after he criticised boss Martin O'Neill's handling of his proposed move to Liverpool.
With Barry due to return to training, he could now be involved in the club's Intertoto Cup clash away to Danish side Odense on Saturday.
A statement on the club's official website read: "The club can confirm that Gareth Barry will be back in training at Bodymoor Heath tomorrow (Wednesday)."