Ruddock goes into the match without first-choice midfield pairing Gavin Henson (groin) and Tom Shanklin (knee), while leading contender Sonny Parker is battling a hamstring injury. The Blues' Jamie Robinson is still finding his feet after a year out with a knee injury and the Dragons' Hal Luscombe is out of the equation after breaking a thumb against Edinburgh on Friday night.
Ruddock has the choice of the Dragons' Ceri Sweeney in the No. 12 jersey, while veteran Mark Taylor may earn a recall if Parker fails next week's fitness test. Skipper Gareth Thomas played at outside centre for Toulouse on Saturday and may move from fullback to fill the problem area.
World-class prop Gethin Jenkins (shoulder) will also miss the autumn Test series, while doubts linger over Lions star Ryan Jones after he injured a shoulder against Bath a week ago. Ironically, the man in the Bath No. 8 jersey that day is being tipped as Jones's replacement in the Wales lineup.
Gareth Delve has been tipped as a Wales star for several years, but a serious shoulder injury meant his 2003 match against the Barbarians is his only match in the red jersey. But after an eye-catching performance in Bath's Powergen Cup victory over the Ospreys, his name is back in the headlines.
"I got a text from Scott Johnson after the Ospreys game, asking if Gareth was available for Wales squad training," Bath coach John Connolly said. "Gareth is a big, strong man. He's incredibly athletic, he's a massive ball-carrier, a good defender and he has the physicality for Test rugby.
"I think Gareth will be involved in the autumn. Ryan Jones is a good player, but he took another knock against us so you don't know. And Colin Charvis is competing with Gareth - I think Charvis is an openside flanker. I think you'll see Gareth in the 22 for the autumn Tests."
Connolly said the most exciting thing about Delve was that he still had a lot of improvement in him after his horror run of injuries.
"Gareth is definitely on an upward spiral - he didn't play for three years and it's always going to take a year to come back into it," the Australian said. "He came into some form slowly last year and he's really stepping up to the mark this season. Against the Ospreys, he was the best backrower, and the best thing is that you know he has a lot of improvement in him."
The Webb Ellis Cup visited Lampeter on Monday to recognise the fact that the town is celebrating a major milestone as it is believed the first ever game of rugby played in Wales, was in fact played in Lampeter 150 years ago.
Cardiff Blues U18 Girls will go into Sunday's Gemau Cymru with an extra spring in their step after Welsh internationals Elinor Snowsill and Philippa Tuttiett offered some last minute tips at a training session earlier this week.
Rob Howley and Josh Lewsey addressed more than 250 community club coaches and referees at the first WRU National Community Conference on the weekend. The volunteers benefitted from coaching masterclasses and workshops in a bid to connect all levels of the rugby pathway in Wales.
UEFA has today confirmed the Football Association of Wales (FAW) has been successful in its bid for the Millennium Stadium to host the 2017 UEFA Champions League Final on Saturday 3rd June, 2017 (kick-off: 19.45hrs GMT).
The winners of a filmmaking competition organised by the education charity Into Film and the WRU enjoyed a behind the scenes tour of the Millennium Stadium - and a chance to be photographed with the WRU's fire-breathing, rugby loving mascot, Scorch The Dragon, and Welsh international, Jake Ball.