Wales captain Dewi Lake has been ruled out of the west Wales derby against the Scarlets after suffering a bicep injury in training this week.

The Ospreys are currently assessing the extent of the hooker's injury, but it's understood to be serious enough to likely concern Wales ahead of the Six Nations.

However, despite Lake's absence, Wales internationals Jac Morgan and Gareth Thomas are fit to start - with the former captaining the Ospreys against his former side.

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New head coach Mark Jones has named his first side since replacing Toby Booth earlier this week, with his future defence coach Justin Tipuric returning to the starting side.

Sam Parry and Tom Botha start in the front-row, with Will Spencer partnering James Fender in the second-row. In the back-row Morgan and Tipuric line up alongside Morgan Morris.

Reuben Morgan-Williams starts at scrum half, with Dan Edwards at fly-half. Keiran Williams partners Owen Watkin in midfield, with Jack Walsh, Keelan Giles and Dan Kasende in the back-three.

“This is a proud fixture that has been around 20 plus years in the current badges, the history goes back a long way," said Jones. "Both teams will be aware of what’s at stake and we’re excited about the opportunity to go up against a very good team.

“Most importantly though, we’ll be looking at our own process and execution. It doesn’t matter who you play in the BKT URC, if you don’t play to your level you’ll get found out.”

While the Ospreys are reeling from a record European defeat and coaching change, the Scarlets head to Swansea on Saturday having started the season positively.

Dwayne Peel makes just two changes to the side that beat Black Lion in Llanelli last week, with Ioan Lloyd and Eddie James starting.

Lloyd replaces full-back Ioan Nicholas, while James starts ahead of Joe Roberts alongside Johnny Williams in midfield. Tom Rogers and Ellis Mee continue on the wings, with Blair Murray ruled out with a hamstring issue.

Half-backs Sam Costelow and Gareth Davies start once again, while Peel has opted for the same forward pack that started last weekend.

Alex Craig, who missed last Sunday’s game because of illness, comes into the match-day 23.

“Derbies bring a different type of intensity and emotion," said Peel. "Nothing gets your blood going like a West Wales derby.

"As soon as the game was finished on Sunday, all the focus was switched to this game. It is a fantastic occasion, brings rivalry, bragging rights. I have been lucky to be part of it as a coach and as a player – some great teams and players have played in these fixtures.”

Ospreys: Jack Walsh; Dan Kasende, Owen Watkin, Keiran Williams, Keelan Giles; Dan Edwards, Reuben Morgan-Williams; Gareth Thomas, Sam Parry, Tom Botha, Will Spencer, James Fender, Jac Morgan (capt), Justin Tipuric, Morgan Morris.

Replacements: Lewis Lloyd, Garyn Phillips, Rhys Henry, Will Griffiths, Morgan Morse, Kieran Hardy, Evardi Boshoff, Iestyn Hopkins.

Scarlets: Ioan Lloyd; Tom Rogers, Johnny Williams, Eddie James, Ellis Mee; Sam Costelow, Gareth Davies; Kemsley Mathias, Marnus van der Merwe, Henry Thomas, Max Douglas, Sam Lousi, Taine Plumtree, Josh Macleod (capt), Vaea Fifita.

Replacements: Shaun Evans, Alec Hepburn, Archer Holz, Alex Craig, Jarrod Taylor, Archie Hughes, Joe Roberts, Ioan Nicholas.