Portsmouth boss Grant confirms Tosic capture
Grant has been keen to strengthen his options as he battles against relegation and he has taken the 25-year-old on a short-term deal.
"He's not under contract so we could sign him (outside the transfer window)," Grant told Sky Sports News.
"He played for Werder Bremen and I think he could help us because we don't have enough defenders, and he can full-back and in the middle."
Tosic has been awarded a work permit and he could go straight into the squad to tackle fierce rivals Southampton in the FA Cup this weekend.