Lukas because Boro's second signing of the transfer window on January 3 2019, linking up on loan from Manchester City until the end of the season.
A striker who can also operate on the wing, Lukas spent the 2018/19 season on loan at Championship side Preston, making his debut away to Swansea City.
He bagged his first senior goal in a 1-1 draw at home to Aston Villa in December 2018. He netted a further three times for the Lilywhites, including a brace against Ipswich Town.
He played against Boro twice last season for Preston in the Championship.
Lukas switched allegiances in March 2019 to Germany, and made his debut for their U21s in the 2-1 win against England. Dael Fry lined up against him in that game having previously been his international teammate.
He was part of the Germany U21 squad for last summer’s Euros, who lost out to Spain in the final. He made three appearances during the tournament.
Lukas linked up with Bundesliga outfit Wolfsburg on loan at the start of this season. He played 12 times in all competitions for them.