Tommy Smith last played for Colorado Rapids, who he joined just over two years ago after spending his entire career to that point on the books of Ipswich Town.
The 29 year old made over 60 appearances in the MLS, netting seven goals, before declining a new contract offer in November in favour of a return home.
The New Zealand international made 267 league appearances as an Ipswich player, and was a favourite of former Sunderland managers Roy Keane and Mick McCarthy. However, he struggled with fitness towards the end of his time with the East Anglian club and was eventually allowed to leave in order to take on a new challenge in the USA.
Standing at 6’2, Smith is similar to Bailey Wright in stature, and is relatively quick for an aggressive defender. He’s still a good age and it’s surprising he’s still without a club - perhaps a short term deal with Sunderland would work in both his and our favour.
Son of former Sunderland boss Steve, Alex Bruce is currently without a club after leaving Scottish Premiership side Kilmarnock on deadline day.
The 35-year old has had a long and storied career, playing the brunt of his football with Ipswich Town, Leeds United and Hull City - where he was promoted to the Premier League and played in an FA Cup final under the stewardship of his old man.
Last year he formed a formidable part of Kilmarnock’s defence which, under Steve Clarke’s leadership, managed to finish third in the Scottish top flight, qualifying for European football in the process.
Bruce might well be in the final stretch of his football career, but he could be an option if we’re after someone with vast experience, who has only recently stopped playing (so you’d imagine he’s fit) and might not mind acting as back up.
Like Alex Bruce, former Luton Town captain Alan Sheehan was made a free agent on the 31st of January - six months before his contract with The Hatters was due to expire.
Sheehan featured as part of the Luton side that won League One last season but, with opportunities hard to come by in the Championship, he was allowed to leave in order to seek regular first team football elsewhere for the remainder of the current campaign.
The Irish defender played for Phil Parkinson at Bradford, so at least the current Sunderland boss would know what he was getting should he decide to give Sheehan a go.
33-year old defender Jake Wright is another on the lookout for a new club following a deadline day release - this time by Premier League outfit Sheffield United, where he was deemed surplus to requirements.
Wright has actually played a fair bit of football already this season, turning out regularly in the first half of the campaign on loan for bottom side Bolton Wanderers.
Wright has had a storied lower league career, playing the brunt of his football during a six-year spell with Oxford United, captaining the side all the way from the Conference to League One.
Importantly, Wright is a left-sided centre back who predominantly uses his left foot, and he can cover a number of positions. Could his versatility make him an attractive prospect?