Celtic were at the centre of two intriguing developments yesterday after their interest in Sheffield United defender Auston Trusty came to light. The Bhoys are keen on bringing the United States international north of the border just a year after he joined the Blades from Arsenal in a deal worth £5 million. In addition, Sheffield United are in talks with Mikey Johnston and the Republic of Ireland international could have a chance to return to the scene of his excellent performances last term should he opt to move to the Sky Bet Championship. With just a week of the window remaining, it will be…