Head coach Gregor Townsend says Jamie Ritchie faces "a challenge" to retain the Scotland captaincy - and must demonstrate his form and fitness - before the Six Nations.

However, Townsend told the BBC Scotland Rugby Podcast that the Edinburgh flanker is not guaranteed to start the tournament opener against Wales next month because of "the form of the guys in that back row".

"I think he's got to do a bit more than prove fitness," the Scotland head coach added.

"He's got to go into this tournament in his best form. He's obviously got a challenge and he knows he's got a challenge this week to deliver that [for Edinburgh against Scarlets].

"He's more than up for it. That's what you want.

"We want to make sure we're picking a 15, a 23 of players playing their best rugby going down to Cardiff. I hope Jamie will deliver that and make things a bit more straightforward over the weekend."

Townsend named his squad for the 2024 Six Nations on Tuesday.

In his 39-strong select, the Scotland head coach says he has no shortage of candidates to replace Ritchie, who missed Edinburgh's defeat by Gloucester with a jaw issue on Saturday, if he elects not to retain him as captain.

"Our leadership group, I'd imagine we'll produce a captain from that if it's not Jamie," said Townsend, who is preparing for his seventh Six Nations as Scotland boss.

"Rory Darge, we'll know at the weekend if he's available for the Six Nations. He was captain against Italy [in the 2023 Six Nations], Finn Russell was captain against France, Grant Gilchrist was captain against Romania [in the World Cup] and has captained the side before.

"Sione Tuipulotu is in our leadership group and has captained Glasgow, so we have leaders in our squad. Kyle Steyn has been Glasgow captain too.

"We're leaving it for a week, that's really about Jamie and seeing where he is."

Ireland's Andy Farrell was last week confirmed as the next British and Irish Lions head coach for the tour to Australia in 2025.

Townsend, a series-winning Lions Test player in 1997 who returned to South Africa as Warren Gatland's assistant for the 2021 tour, would not be drawn on whether he would be interested in being part of Farrell's coaching team next year.

"These are all hypotheticals," he said. "The head coach has just been announced and I'm sure the last time it took about a year before the assistant coaches were talked to or brought on board.

"My priority is 100% with Scotland just now and doing well in this tournament.

"Andy obviously deserves it with how well he's led Ireland over the last two or three years and his experience of being on Lions tours as assistant coach.

"It was an interesting time [to announce it], it seems so long until the next Lions tour and with the Six Nations coming up as well. Everyone is starting to pick their Lions squads already, so it just shows you how big the Lions is."