Ireland will open their Six Nations campaign at Murrayfield on Saturday, February 4, with Sexton now expected to be fit to start.

"Johnny took a bruised calf in to the game against Castres and it just tightened up," said Schmidt.

"There's not a lot of damage there, nothing's showing up that's overly significant.

"Johnny's already starting back doing a little bit.

"We'd be confident he'll be able to train next week and therefore be fully available to face Scotland."

Sean O'Brien has also been fighting a calf complaint, but Schmidt insisted the Leinster back-rower will also be available for the Scotland clash.

"He's slightly further ahead than Johnny," said Schmidt of O'Brien.

"We're confident he may train before the end of the week fully, but he should train fully next week."

Ireland boss Schmidt has confirmed that uncapped Munster playmaker Rory Scannell will provide the 40-man squad's third option at fly-half.

Schmidt overlooked Bordeaux's Ian Madigan given his situation as plying his club trade overseas, but insisted the former Leinster fly-half could yet come back into the reckoning later in the tournament.

While Scannell operates primarily at centre, Schimdt insisted the fast-improving Munster midfielder would cope if pitched in at 10.

"The first time I saw Rory play for Dolphin against Belvedere he had a fantastic game at 10," said Schmidt.

"There's a big difference between that and Murrayfield but he would be the guy who could cover there.

"We've also got Paddy Jackson available obviously.

"With Ian (Madigan), he could only have done those two first days with us.

"You only get that three-day opportunity with the window. So it complicates that.

"Ian had an injury earlier in the season so he hasn't had a lot of rugby really.

"I've kept in touch with Ian. He would slot back in pretty seamlessly for us, so that's still something potentially that we could look at."