Sexton took a blow to the head during their 34-10 win over Wales in Cardiff at the weekend and had to complete a head injury assessment (HIA) before he could resume training.
Ireland coach Andy Farrell later said that Sexton's issue had been a "slight dead leg".
"Obviously the confusion around the HIA and stuff like that, it's nothing I can control," Sexton said.
"I'll be ready to go for 80 (minutes) this week if needed. I was happy in terms of how I felt physically at the weekend."