"Nobody is giving us a chance so it is a great opportunity for us to go out as underdogs, as we have hundreds of times before, and with a home crowd and hopefully seven or eight thousand people shouting us on," said Muldoon.
"I don't think anyone who puts on the jersey feels like we are going to get hammered - that attitude is long gone. They said last week that they would rest players with this week, and this game, in mind and we are expecting a full 15 coming over.
"We're always fighting with someone about should we be in this competition, are we good enough and are we the fourth team in Ireland? It is just another push-us-down situation that we are used to.
"Results haven't gone our way so far this season and we all know that Saracens will present us with a big challenge."
England and British & Irish Lions outside half Owen Farrell didn't appear in last weekend's win over London Wasps, but is restored to the side along with Lions props Mako Vunipola and Matt Stevens.
Saracens were semi-finalists last year, losing to Toulon at Twickenham, and McCall is hoping to go one step further this season.