Released duo Grant Ward and Tom Adeyemi are interesting their former loan club Rotherham United.
Ward, 24, and Adeyemi, 27, are both out of contract having been told they are surplus to requirements by the Blues at the end of the season.
Adeyemi missed most of 2017/18 with a hamstring problem and then all of last season after picking up an achilles injury in pre-season which eventually required surgery.
The former Norwich youngster only made a total of four starts and one sub appearance for the Blues.
Ward, who made 75 starts and 23 sub appearances for Town, scoring eight goals, saw his 2018/19 cut short when he suffered an ACL injury at QPR on Boxing Day.
"They are definitely players who have come up on our radar,” Millers assistant manager Richie Barker told the Rotherham Advertiser. "They are on a list of players for us to talk about.”
Ward spent 2015/16 on loan with the Millers from Spurs making 35 starts and eight sub appearances, scoring two goals.
Adeyemi was with the South Yorkshiremen, who will join the Blues in League One next season, in 2016/17 from Cardiff, making 29 starts and one sub appearance, scoring seven goals.
"They are both players who have been at this club before,” Barker added.
"The gaffer [Paul Warne] knows them as people and everyone knows how important a player's character is when it comes to us making signings.
"Conversations with them haven't taken place but we wouldn't be doing our jobs properly if we didn't know that both were available.”