Crusaders pair Colin Coates and Chris Morrow are both suspended for Saturday's Premiership game against champions Linfield at Seaview.
The match will be a dress rehearsal for the Irish Cup final between the sides on 5 May, although both managers are likely to rest some key players.
Crues boss Stephen Baxter also has Monday's Setanta Sports Cup semi-final second leg with Sligo to consider.
Portadown lead Cliftonville by two points in the battle for second place.
The Ports travel to Coleraine on Saturday, while Cliftonville entertain Glentoran.
The Reds are without the suspended Mark Clarke, while Eamonn Murray and Andy Waterworth are injury doubts for the Glens.
Murray is suffering from a back complaint and Waterworth is struggling to overcome a virus.
"I have asked the players to build on their performance at Portadown last week," said Glens manager Eddie Patterson.
"We're glad to have secured the signing of Stephen McAlorum for next season as we have been missing a bit of bite in midfield - hopefully there will be a couple more signings to follow," added Patterson.
Ballymena hope to extend their run of 10 unbeaten games at home to Glenavon, who are one of three clubs in danger of being involved in the promotion/relegation play-off with Newry City.
Another of those clubs, Dungannon Swifts, face a Donegal Celtic side who have conceded 10 goals in losing their last three games since the league split in March.
Saturday 21 April - Carling Premiership - 1500 BST kick-offs
Ballymena Utd v Glenavon
Cliftonville v Glentoran
Coleraine v Portadown
Crusaders v Linfield
Dungannon Swifts v Donegal Celtic