Striker Sébastien Haller is to join Istanbul club Besiktas on loan from Bundesliga side Borussia Dortmund for the rest of the season, Turkish news reports said on Monday. The reports said that Besiktas, who are sixth in the Süper Lig, will take over the salary of the 29-year-old. Haller is to replace Cameroon’s Vincent Aboubakar who was dropped from the Besiktas squad last month. Haller joined Dortmund from Ajax Amsterdam in July 2022 and was diagnosed with testicular cancer shortly afterwards. He returned to action after an operation and treatment in January 2023 but has only started in four …