The New Zealand number eight missed the Christmas period wins over Ospreys and Dragons.

Scarlets have made three changes from the team that defeated Ospreys 44-0.

Werner Kruger, Tevita Ratuva and Uzair Cassiem all come into the pack with Samson Lee, Sam Lousi and Blade Thomson dropping to the replacements bench.

Wing Johnny McNicholl is still missing with an ankle injury, while Wales prop Rob Evans has a neck problem.

Cardiff Blues have made five changes as they target a hat-trick of Welsh derby wins with head coach John Mulvihill naming an unchanged backline but reshuffling his pack.

Props Rhys Gill and Scott Andrews come into the front-row for Brad Thyer and Keiron Assiratti, while Filo Paulo replaces James Ratti in the second-row.

There are two further changes in the back-row with Williams making his comeback from injury and Will Boyde returning to face his former side. Josh Navidi continues in the back-row and captains the side.

Wales prop Dillon Lewis is also close to a return but may not feature until the European games against Leicester on 12 January and Calvisano the following week.

"We've refreshed a little bit because this will be the third game in 13 days so they come thick and fast, and there's also that collision that is usually higher in derbies than in normal Pro14 games," said Mulvihill.

"So a few bumps and bruises but the squad is pretty similar.

"Last week against the Dragons was the first time that Cardiff Arms Park has been sold out for a while and the atmosphere was electric here.

"We're really looking forward to this week, we're really excited about it, we've had a really good week at training and I don't think the club has gone three up at Christmas at any point.

"We want to be the first to do that. If you win two you'd be pretty happy but if you win three you'd be over the moon."

Scarlets sit third in the Conference B table, four points ahead of the Blues after nine rounds of action.

"They are a good side, well coached, but we are excited by the challenge and the prospect of playing in front of a packed crowd in the capital," said Scarlets forwards coach Ioan Cunningham.

"The conference standings also add an extra spice to it."

Cardiff Blues: Amos; Lane, Lee-Lo, B Thomas, Adams; J Evans, T Williams; Gill, Belcher, Andrews, Paulo, Turnbull, Navidi (capt), Boyde, N Williams.

Replacements: E Lewis, Domachowski, Assiratti, Ratti, Robinson, L Williams, Tovey, M Morgan.

Scarlets: Halfpenny; Conbeer, Hughes, Parkes, S Evans; O'Brien, G Davies; W Jones, Owens (capt), Kruger, Ball, Ratuva, Shingler, Macleod, Cassiem.

Replacements: Price, Elias, Lee, Lousi, Thomson, Hardy, Lamb, Asquith.

Referee: Frank Murphy (Ireland)

Assistants: Adam Jones (Wales) & Eddie Hogan-O'Connell (Ireland)

TMO: Simon McDowell (Ireland).