Sheffield United manager Kevin Blackwell has confirmed he has taken Shaleum Logan, Gregory Vignal and Kerrea Gilbert on trial.
The Blades boss is keen to bolster his defensive options ahead of the new Championship season and is running the rule over the trio.
Logan joins from Manchester City, former Birmingham and Liverpool man Gregory Vignal is out of contract while Gilbert has linked up with the south Yorkshire side from Arsenal.
The trio could all feature in Tuesday's friendly against Burton Albion on Tuesday night with the aim of impressing Blackwell and earning an extended stay.
"We're looking at Manchester City's Shaleum Logan for a week, Birmingham's Gregory Vignal is out of contract and Kerrea Gilbert is with Arsenal," he told the club's official website.
"They have all been recommended and might possibly all be involved on the night (against Burton)."