Portadown's in-form striker Matthew Tipton believes the title chasers will have to be at their best to beat Crusaders at Seaview on Saturday.
"They are a good team, they were strengthened in the summer and it will be very tough for us," said Tipton.
Ports midfielder Shane McCabe is suspended while Paul Leeman (calf) is ruled out for Crusaders.
Cliftonville defender Liam Fleming (hamstring) will miss the Solitude showdown with Donegal Celtic.
However, the Reds welcome back Ciaran Donaghy after a leg injury.
Glentoran midfielder Ciaran Martyn is ruled out of the Oval encounter with Ballymena United because of a hamstring injury.
Glens boss Scott Young has striker Andy Waterworth back after a calf injury and Jamie McGovern returns from suspension.
Carrick Rangers forward Stephen O'Neill is back to face leaders Linfield at Windsor Park after three weeks out with a hamstring injury.
Rangers manager Stephen Small will give late fitness tests to keeper Chris Keenan and Liam Hogan.
Dungannon Swifts are depleted ahead of the visit of Lisburn Distillery with Ryan McCluskey, Johnny Topley, Ryan Mullan and Michael McKerr all ruled out.
Coleraine travel to Glenavon without Kyle McVey and Michael Hegarty, who face long-term injury lay-offs.
Saturday 24 September - 1500 BST kick-off
Cliftonville v Donegal Celtic
Crusaders v Portadown
Dungannon Swifts v Lisburn Distillery
Glenavon v Coleraine
Glentoran v Ballymena Utd
Linfield v Carrick Rangers