Promotion candidate Union Berlin have signed Japanese defender Atsuto Uchida with immediate effect on a deal that runs through June 2018, the German second-tier side said Monday.

(Union Berlin)

The 29-year-old Uchida, who spent seven years with Schalke in the Bundesliga, will reunite with his former Schalke manager Jens Keller as Union Berlin look to return to the top flight after finishing fourth last season.

"I'm looking forward to finding out what awaits me," Uchida said on the club's official website.

"Of course I know Jens Keller well. I'm very happy that I'll be able to play soccer again," he said.

Uchida joined Schalke in July 2010, after the World Cup in South Africa from the J-League's Kashima Antlers.

He has battled injuries to his right knee over the years. Since having surgery on the knee in 2015, he has made just one appearance across all competitions -- in December 2016 in the Europa League.

Capped 74 times by Japan, Uchida played 104 Bundesliga matches for Schalke.