Aplon and Louw were released from the Springbok squad after playing in the past Saturday's defeat to the All Blacks in Soweto. Aplon has been included at wing, while Louw will be returning to the flank.
His return couldn't have come at a better time for the coach after WP lost their two starting flanks against the Natal Sharks last weekend through injury. Reynhardt Elstad underwent surgery to a broken thumb on Tuesday and he will be out of action for nine weeks.
Pieter Louw has a rib injury and Coetzee said he would probably be out for one or two weeks. Nick Koster and hooker Deon Fourie replaced the injured duo last weekend.
Coetzee said he was delighted to have the Bok duo of Aplon and Louw back. "We are all buoyed by the announcement that they can join us. I had no doubt in my mind to put them in the starting line-up.
"Obviously these Springboks come with experience and that will come in handy this weekend."
The coach lauded Aplon and said he has been in outstanding form the whole season. "'I think he's been outstanding throughout the season. He played in the Super 14 and I think he played well.
"It's not really for me to talk about Springbok selection. I am just happy to have Gio back. I don't think Gio will lack motivation playing for WP. I spoke to him and Francois Louw today and they are looking forward to play."
Coetzee said with two flanks out the return of Louw was perfect timing. "Having lost two flanks and then getting back a Springbok flanker would definitely help."
Looking back to last weekend's first defeat of the season, Coetzee said the important thing for the squad was to learn from their mistakes. "We got to start all over again.
"We had a bit of a - not a setback - but a loss last weekend, but it's not the end of the world. At some stage you lose a match in this competition, but better now than later.
"We learnt from that game last weekend. We need to make sure that we become stronger going into the second round. We had a good look at ourselves. We know it's about going back to the basics and getting it right, making sure we do the things right that made us win six games in a row and that was the focus this week.
"We have another opportunity this coming weekend to fix what went wrong last week. We will try and fix it this week. No doubt the Cheetahs will probably have a good look at the way the Sharks played against us.
"We want to make sure that we get it right up cause this Cheetahs side is really a good side as well."