The Terriers are struggling for form at the moment, and have won just one of their last five outings in the league.
A defeat to Preston North End on Saturday left them 19th in the table, just seven points clear of the relegation zone.
For their part, two wins in three have lifted Birmingham out of the bottom three, and a win over Town would take them above Carlos Corberan’s men in the table.
The Blues scored twice in the last 10 minutes to beat QPR 2-1 on Saturday afternoon.
And looking ahead to Tuesday’s clash, Prutton believes that they can keep their mini-revival going.
Speaking to Sky Sports News, he said: “Huddersfield may be starting to worry a little.
"That win against Swansea a couple of weeks ago is starting to look like a blip rather than the start of a recovery for Carlos Corberan and his side.
“This is a massive game. Birmingham got a huge win at the weekend to lift themselves a little away from the bottom three.
"Both sides will be desperate for victory to give themselves some more breathing space, but I feel the Blues will have more confidence now and may well sneak the win.”
Prutton forecasts a 1-0 defeat for Huddersfield.
The Terriers lost their last encounter with the Blues back in October, with Lukas Jutkiewicz’s last minute strike enough to secure a 2-1 City win.