Leeds United have made an approach for Werder Bremen’s Ilia Gruev with the club focusing heavily on central midfielders in the closing days of the transfer window.United manager Daniel Farke is keen on £4m-rated Gruev, the 23-year-old Bulgaria international who has been with Werder Bremen since breaking through from their youth set-up in 2019.Leeds completed their sixth signing of the summer on Wednesday morning by announcing right-back Djed Spence on a season-long loan from Tottenham, but increased options at central midfield are a major priority before the window closes on Friday night.Gruev, who made 31 Bundesliga appearances last season, primarily operates as a defensive midfielder.Despite the window being at such an advanced stage, Leeds are continuing to weigh up their options, having tracked Rangers’ Glen Kamara for several weeks without closing a deal.The club were heavily linked with Norwich City’s Kenny McLean on Monday, although Norwich are believed to be reluctant to sell a player who Farke worked with at Carrow Road.Sources in Scotland are also crediting Leeds with a firm interest in Celtic’s Matt O’Riley, a 22-year-old who started out at Fulham.O’Riley, however, has been fully involved in Celtic’s season to this point.