Tosic has signed on loan from Premier League crisis club Portsmouth until the end of the season and will be added to the squad once the Football League have cleared the move.
The Serbian defender is likely to start at left-back after Matt Connolly suffered a recurrence of his ankle injury during Tuesday night's 1-1 draw against Derby.
Warnock will check on Lee Cook, who scored his first goal since Boxing Day 2008 against the Rams.
The winger lasted an hour as he continues to build up his fitness following another knee operation last summer.
Midfield duo Martin Rowlands and Gavin Mahon remain long-term absentees with knee injuries.