Howard, 29 (pictured) looks set to depart Bramall Lane this summer after he told friends that he does not expect to be given a new contract to remain with the club.
Since joining the club in February 2012 (after being released by Blackpool) the keeper has played almost 80 times under 5 different managers but despite being handed the Number One jersey at the start of the 2015/16 campaign he eventually lost pole position to George Long and has been a substitute for the majority of this season.
His departure could force Blades boss Nigel Adkins to search elsewhere or recruit from the Academy with both Aaron Ramsdale and George Willis impressing.