Head coach Aitor Karanka has said Middlesbrough are working with Premier League side Chelsea on a deal to sign forward Patrick Bamford on loan.
Bamford, 20, spent five months at Derby last season, scoring eight goals in 23 appearances for the Rams.
The England Under-21 international has also had two loan spells at MK Dons since joining the Blues from Nottingham Forest in January 2012.
"We are working on Bamford," Karanka said after Boro's 1-0 defeat by Leeds.
"I have spoken with Jose Mourinho, everybody knows how important a player he could be for us.
"I hope that he can be with us but it is not in my hands.
"We would like to have a squad with a lot of quality so there is competition for the players."
Boro have completed the deal to sign defender Damia Abella following his departure from Osasuna after international clearance was received before kick-off.
Abella, 32, played the full 90 minutes at Elland Road as Leeds ended Boro's 100% record for the new campaign.