[4] Sam Stubbs and Djed Spence then joined the reserves, both on free transfers, arriving from Wigan Athletic and Fulham respectively.

[7] On 8 August 2018, Middlesbrough completed the signing of Jordan Hugill from West Ham United on a season-long loan deal.

[11][12] Players who were loaned out included Joe Fryer to Carlisle United,[13] Hayden Coulson to St Mirren,[14] Luke Armstrong to Gateshead,[15] George Miller to Bradford City.

[16] The club then said their goodbyes to their team superstars: striker Patrick Bamford to Leeds, centre-back Ben Gibson and winger Adama Traoré.

[17][18][19] As part of their pre-season preparations, Middlesbrough faced Sturm Graz, Spennymoor Town, SV Sandhausen, Accrington Stanley, Rochdale and Hartlepool United.