A 14-man Scarlets team were knocked out of the Heineken Cup by Perpignan last Friday after Wales international backrower Dafydd Jones was sent off for stomping in the ninth minute.
'It was a bad result for Llanelli and for Wales, but it wasn't a great result for Cardiff either,' Young said in the buildup to Saturday's Principality Cup semi-final double-header at the Millennium Stadium.
'They're a wounded animal now, and over the years Llanelli have proven to be at their most dangerous immediately after a loss like that.'
Young has named a predictable side, although injuries in his backline means young fly-half Nicky Robinson moves to fullback and Wales No 15 Rhys Williams slots in on the right wing.
Llanelli coach Gareth Jenkins has replaced Tongan winger Salesi Finau with Wales international Mark Jones to 'combat Cardiff's biggest asset - their pace'.
Scrum-half Dwayne Peel is out with a twisted ankle and has been replaced by Guy Easterby, with the hugely promising Mike Phillips coming on to the bench.
'I've been very impressed with this boy,' Jenkins said of the 6ft 3in Phillips, a Wales Under-21 international. 'He is exceptional.'
Llanelli winger Garan Evans plays his 250th game for the club on Saturday, earning life membership to the club.
'He'll be able to walk freely through the gates of Stradey Park for the rest of his life, and it's great that he's a local boy,' said Jenkins, himself a life member. 'There's not a nicer guy playing rugby.'
Cardiff: N Robinson; R Williams, J Robinson, P Muller, C Morgan; I Harris, R Powell; K Fourie, P Rogers, B Evans, H Senekal, J Tait, R Sowden-Taylor, M Williams (capt), E Lewis.
Replacements: J Yapp, L Collins, L Tait, J Brownrigg, R Smith, M Allen, D Dewdney.
Llanelli: B Davies; M Jones, M Watkins, L Davies, G Evans; S Jones, G Easterby; I Thomas, R McBryde, J Davies, V Cooper, C Wyatt, D Hodges, S Easterby, S Quinnell.
Replacements: M Madden, A Gravelle, L Gross, I Boobyer, M Phillips, G Bowen, S Finau.