Celtic are set to seal the signing of Arne Engels on transfer deadline day, which will be the biggest incoming transfer in the club’s history. Engels is an emerging midfield talent at Augsburg and has become the club’s primary consideration to replace Matt O’Riley, who left the club for Brighton & Hove Albion earlier this week. Celtic will pay as much as £11m for Engels, shattering the existing upfront fee transfer record and delivering a significant statement of intent ahead of an upcoming expanded Champions League. Sky Sports reports that the Belgian star will undergo his medical today. Pers…