BERLIN, Jan. 22 (Xinhua) -- Wolfsburg signed Hoffenheim goalkeeper Koen Casteels until June 2018, the "Wolves" confirmed in an official statement on Thursday.

The 22-year-old goalkeeper penned a three-and-half-year contract with Wolfsburg. However, the goalkeeper will spend the second half of the campaign at struggling side Werder Bremen on loan.

"Koen Casteels is an interesting goalkeeper with great potential. We will now monitor his further development," Wolfsburg manager Klaus Allofs said.

The former Under-21 Belgian international will be the back up of Bremen's goalkeeper Raphael Wolf.

"We loaned a young but experienced Bundesliga keeper. He will give us more options on this position. However, our number one, Raphael Wolf, will be perfectly backed by Casteels and Richard Strebinger," Bremen manager Thomas Eichin said.

Casteels joined Hoffenheim from KRC Genk in 2011 to make 39 appearances with the first team. His new side Wolfsburg sit currently on second place of the standings, eleven points adrift of front-runners Bayern Munich, meanwhile Bremen occupy a relegation play off spot.