Zubrus, acquired from Washington in a trade deadline deal in March, has been hampered by a lower body injury that limited him to just four minutes of ice time in Buffalo's 3-2 win in Game 4 on Wednesday.
Stafford has played in nine playoff games this postseason, registering four points. Paetsch has not appeared in a playoff game but had 24 points in 63 regular-season games.
Ruff said on Thursday he would probably shift Ales Kotalik or Adam Mair to center while keeping intact the all-center line of Derek Roy, Chris Drury and Tim Connolly. The trio was effective in Buffalo's first win of the best-of-seven series.