Looks like Tindall was only assistant until the end of the season https://theathletic.com/news/sheffield-united-jason-tindall-coaching-staff/68dgQpTbxzr3/
Jason Tindall, Eddie Howe’s long serving assistant at Bournemouth, has joined Sheffield United's coaching staff until the end of the season.
He isn't listed on https://www.sufc.co.uk/players/staff/