The club have completed the signing of Toyosi Olusanya on a two-year contract.
The striker joins after spending last season with National League South side Billericay Town.
Toyosi has previous EFL experience with AFC Wimbledon, where he graduated from their youth team to score on his debut.
He has since had trials with a number of Premier League clubs including Chelsea and Wolves, while he was also reportedly attracting interest from Newcastle United and Manchester City.
Boro boss Neil Warnock said: "I wanted to give him an opportunity.
"I came from non-league myself, I watched him play and I just had hunch. He knows Isaiah [Jones] too which is a plus.
"I hope he enjoys himself here, it's a big ask but I hope he can excite everyone here like he excites me. He's got a great attitude."