The Bit O' Red are aiming to reach their first Setanta Sports Cup final but must overcome the SSE Airtricity Premier Division champions
Rovers will be without Danny Ledwith, Joseph Ndo, Gavin Peers and Raffaele Cretaro who are all out injured. Keith Fahey and Kenny Browne are both doubts for St Pat's ahead of the game.
Despite suffering a 1-0 defeat at home against Dundalk in their last game out, Sligo Rovers boss Ian Baraclough took the positives from the game and is expecting a close encounter against Liam Buckley's men.
"Yes we were beaten, but there were a lot of positives to take," Baraclough told the official club website.
"There was a big disappointment in the dressing-room after the game but a couple of days later, we reflect and can be pleased with how we reacted and now comes an opportunity to reach a cup final.
"I think it will be a tight affair. It could be cagey - both sides know each other very well. We know it’s a big time in our season.
"It's so early in the year but here we are with a cup semi-final and a match away to Shamrock Rovers in the league on Friday that will be important and we can’t wait to play the games."