Sebastian Polter has returned to FC Union Berlin after completing a £3m switch from Queens Park Rangers.
The 25-year-old passed his medical on Tuesday and signed a three-and-a-half year deal with the Bundesliga 2 side.
Polter enjoyed a productive spell on loan at Berlin during the 2014-15 season, scoring 14 goals in 29 appearances.
The former Germany under-21 international had not featured for QPR since their 1-0 home defeat to Derby on December 14.
Polter, who joined QPR from Mainz in July 2015, scored 11 goals in 56 appearances during his 18-month spell at Loftus Road.