Ghana look set to make three changes for their Africa Cup of Nations Group B clash with Mali.Isaac Vorsah could replace Jerry Akiminko, while Derek Boateng may make way for Mohamed Rabiu, with Harrison Afful preparing to come in for Christian Atsu, who had a poor opener.Ghana have two injury worries - Richmond Boakye and Anthony Annan.Mali coach Patrice Carteron has no injury concerns, but admits he will change his team's tactics.Former Barcelona star Seydou Keita - who inspired the Eagles against Niger and scored their winning goal - will once again be key to how well Mali play, as they look to build on their early advantage in Group B.Black Stars defender Afful can offer the Black Stars more strength on the left, after DR Congo playmaker Tresor Mputu Mabi exposed some weaknesses on that flank in their opening game, a 2-2 draw last Sunday.The two sides are no strangers - they met twice at the Africa Cup of Nations last year, with Ghana winning the Group D game 2-0 and Mali claiming third spot in the play-off with a victory by the same margin.