Transfer interest is building around Arne Engels, with Sunderland understood to be weighing-up a move for the Celtic midfielder. While there has been no official bid as yet, the club may act swiftly if they decide to pursue the deal before the transfer window slams shut. Sunderland remain optimistic, but the deal is not without hurdles. Fulham, Nottingham Forest and Leipzig continue to monitor developments and could yet re-enter the race if negotiations stall or valuation gaps remain unresolved. Sunderland are only scoring 1.04 goals per game (29 in 28) this season, which suggests they need more creativity in the middle. Arne Engels would be seen as the link to raise the tempo and feed the attack. Celtic continue to be linked with Benjamin Tahirovic while Sunderland are also rumoured to be tracking Liam Delap. Need more Sunderland transfer rumours? Stay tuned to PlayerSwitch for live transfer news and rumours from across the world of football.