English midfielder Billy Mitchell, 25, is set to depart Millwall when his contract concludes this summer. He has spent his entire career with the club and made almost 200 appearances. According to Football League World, the midfielder turned down an extension offer from the club. In the 2025/2026 Championship season, he made 29 appearances and provided one assist. Stoke City has released midfielders Lewis Baker and Steven Nzonzi, and Mitchell is viewed as a player who fits the club's requirements. His potential addition on a free transfer is considered a notable acquisition. Watford has also been linked with the player, whose Transfermarkt market value is €3.00m.