Lewis Milne joins fellow midfielder Pablo Navas and striker Liam Cusack in missing Cowdenbeath's Ramsdens Cup semi-final through injury.
Defender John Armstrong is suspended for the all Division One tie, while striker Zeph Thomas is on international duty with St Kitts and Nevis.
But Joe Mbu and Dean Brett are expected to shake off knocks to feature.
Partick Thistle defender Alan Archibald is an injury doubt, but midfielder Sean Welsh is included in the squad.
Neither club has appeared in a Challenge Cup final since the tournament was launched in 1990.
Thistle lost for the first time in Division One last weekend, 3-1 away to Morton, to drop behind Dunfermline Athletic at the top of the table.
Cowdenbeath lie fifth and lost in the only meeting with Thistle this season, 2-1 in Glasgow.
Cowdenbeath player-manager Colin Cameron: "There was very little between us when they won 2-1 at Firhill recently.
"If our players can go out and believe in themselves, they can reach a cup final, which would be an amazing achievement."
Partick Thistle manager McNamara: "Cowdenbeath are a very well organised team who will work all day for their manager.
"We beat them recently, but it was a really tight game, so we have to go to Central Park and make things happen as opposed to waiting for them to happen.
"We have the opportunity to create a first, but we will only do that if we go out and play well."