There are two Danske Bank Schools' Cup quarter-round ties in Belfast, with Methodist College entertaining Wallace High at Pirrie Park and RBAI facing a tight tie against Limavady Grammar at Osborne Park.
Inst welcome back a couple of vital players after injury. Ulster Schools' out-half John McClure is an inspirational player and his presence will increase confidence.
Andrew McGrath has been out with a pulled hamstring for a few weeks and he hopefully returns to No 6 but they will miss second row Cameron Magee who damaged his shoulder in training.
Coach Richard Hedley expects a close game. He said: "We hope to be at full strength for one of the few times this season and know that Limavady will be coming to win.
"They eliminated us in the Medallion Shield two years ago so with that squad I'm glad we're at home. We have shown a lot of potential to play good rugby but every cup tie is different and it will all depend on the day."
Limavady coach Stephen Barr has not been over-happy with their last two cup ties.
"We won but the margins should have been greater," he said. "We have proved that we can face most of the other teams with confidence so I can only hope that ' we turn up' on Saturday."
In the previous rounds Limavady defeated Friends, 21-10 and Dalriada 14-7 while Inst had a 22-10 win at Regent House. Inst, with home advantage, will be expected to progress.
Armagh Royal crushed Coleraine Inst 36-0 but they can expect much harder opposition at Bangor Grammar, a team that has been improving under the coaching of Jason Morgan.
This will be the last game at Ballymac so it is hoped that a number of former pupils who have represented their Province and Ireland will be there.
One such person is the Armagh Royal coach, Kenny Hooks, a former Ireland winger, and he is looking forward not only to the tie but to renewing old acquaintances. "This will bring back memories but the more serious matter is the cup," said Hooks.
"Bangor will certainly be up for the game as they have recently recorded a few good wins in the competition. It will be an interesting encounter and hopefully it will be an open game."
Armagh have a formidable front row and an attacking half-back pairing of twins Ali and Conor Wright.
Luke Rainey is outstanding in the centre and John McDonagh can attack from deep.
Bangor have two brilliant forwards in Max Montgomery and Matthew Stockton and Peter Eves is the perfect link at scrum-half but, all in all, Armagh would appear to be that little bit stronger.
In the other tie Ballyclare High take on Sullivan Upper.
The Holywood team are young and have only a couple of losses to mar their record. Their captain Ross Todd captained the Medallion side that won the Shield two seasons ago and still has another year at school.
They have an effective half-back pairing of Charlie Burrowes and Mark Adair but will need to be at their best to win at Ballyclare.
The High School have four sets of brothers in the line-up and with their usual strong pack they must start favourites, especially at Rashee Road.