Boro find themselves in the thick of the transfer gossip at the moment as the Djed Spence saga continues.
The future of Spence may determine how much Boro boss Chris Wilder can spend this summer as speculation linking the defender with a move to Tottenham Hotspur or Nottingham Forest continues.
Boro themselves have already been linked with several players this summer including Premier League youngsters Cameron Archer and Aji Alese.
Boss Wilder is believed to be interested in bringing in a goalkeeper this summer as well as strengthening his attacking options but what free agents should the Teessiders be considering?
As players up and down the country get set for their release from clubs at the end of the month, we look at some of those heading out of contract who could be of interest to Boro this summer.
5. Naby Sarr
Boro fans don't have to cast their minds back too far to remember the impact of Sarr after the defender scored and helped preserve a clean sheet for Huddersfield Town at the Riverside in April. The 28-year-old, who featured in the play-off final in May, is a free agent after leaving the Terriers. (Photo by Stu Forster/Getty Images) Photo: Stu Forster
6. Alfie Mawson
Mawson will leave Championship winners Fulham this summer and is available on a free after a proposed move to Birmingham City collapsed. (Photo by Catherine Ivill/Getty Images) Photo: Catherine Ivill
7. Conor Hourihane
Interest in Hourihane is expected to be high after the midfielder's exit from Aston Villa. The Irishman has spent time on loan with Swansea City and Sheffield United over the last 18 months. (Photo by Oisin Keniry/Getty Images) Photo: Oisin Keniry
8. Jed Wallace
Wallace is set to end a six year spell with Millwall and has plenty of potential suitors according to reports with West Bromwich Albion believed to be at the front of the queue. (Photo by Clive Rose/Getty Images) Photo: Clive Rose