The Nerazzurri go into the encounter at the San Siro on the back of last weekend's 1-0 defeat at Genoa.
The result extended Inter's winless run to four games across all competitions.
The Nerazzurri have just one victory in their last seven matches overall and pressure is starting to mount on former Napoli boss Mazzarri.
"I knew at the start of the season that it could be difficult to coach a club like Inter," Mazzarri said. "However, we began the campaign really well, above our expectations.
"We then had a drop in form which was partly our fault and the merit of our rivals.
"Life is made of positive and negative moments and football is just like that.
"I don't know if this is the most difficult time of my career as coach, I'm just focusing on the task at hand.
"We have to continue to work hard and we have to turn things around with a victory. We are still fifth in the standings and all is not lost."
Lack of goalscoring has been Inter's main problem, with the Nerazzurri having found the net just once in their last four games.
Fortunately for Inter they take on one of the leakiest defences in the competition with Catania having given away 37 goals in 20 games.
Catania fell 3-0 against Fiorentina last weekend to spoil Rolando Maran's return to the Catania hotseat.
Maran, who started the campaign in charge of Catania but was replaced by Luigi De Canio in October, had expected a different performance from his players.
"We conceded three goals very quickly after allowing Fiorentina so little," Maran said. "The reaction of my players should have been different.
"We clearly have a lot of work to do."
The outcome followed a 2-1 loss at Atalanta in the league and left Catania at the foot of the standings, four points away from safety.
The visitors will be without midfielder Pablo Barrientos, who serves a one-match ban.
Inter midfielder Freddy Guarin, who came close to signing for Juventus this week only for the deal to collapse, will be on the bench against Catania.
Rodrigo Palacio will play in support of Diego Milito in Inter's attack.