Haller was diagnosed just weeks after signing a four-year deal with Dortmund.

"It's been a tough six months but I am happy to be here," Haller, 28, told reporters at Dortmund's training camp in Marbella on Monday.

Haller, who appeared at the Ballon d'Or ceremony in Paris in October, hopes to feature for Dortmund against Augsburg in their first league match of the year on 22 January.

"I am happy to be here with the guys and able to play in this great weather and these facilities," the Ivory Coast international said.

"Of course everything is possible. I have no restrictions in my mind. The only people who can give me restrictions are the coach and the medical staff. I will do my best to play on the 22nd."

The former Eintracht Frankfurt and West Ham player had a successful spell at Dutch champions Ajax, scoring 34 goals, before joining Dortmund.

Haller represented France at youth level before switching allegiance to Ivory Coast, and has also previously played for Auxerre and Utrecht.

Dortmund are sixth in the Bundesliga, nine points behind leaders Bayern Munich, after 15 games of the season.