Jones has been impressive form for the Scarlets since overcoming the second of two knee reconstructions, with recent performances in the European Cup catching the selectors' eye.
Ruddock said: "It's great to see Mark Jones in the squad after two very serious knee operations.
"He is a recognised finisher, try-scorer and line-breaker and you have to be impressed by his determination to get himself back on the field after such serious injuries.
"We also have the Scarlets to thank for the role they have played in supporting Mark's return to fitness and form."
Jones joins Gareth Delve, Matthew Rees and Barry Davies as the newcomers to the squad which featured during the November internationals.
Uncapped Delve, who has been dogged by injury over the last two years, is rewarded for his blockbusting displays for Bath this season with a place in the 30-strong squad.
Ruddock said: "This is the first chance I've been to be able to pick Gareth Delve, who has needed game time since a long lay-off.
"He is catching the eye at the moment and it is nice to be able to call on someone of his quality.
"He looks to have a big future in front of him and I would like to thank Bath Rugby and their management team for the way they have nurtured his talent and supported him through his time out with injury.
"They have not tried to rush him back and hopefully, now that he is playing regularly, he will remain injury-free for some time."
British & Irish Lion Gavin Henson and Ospreys colleague Ian Evans have been omitted from the squad while they complete their suspensions, but Ruddock insists they remain in his selection plans for later in the tournament.
The duo are unavailable for opening match against England on February 4 and Scotland a week later.
"There is every chance Evans will be added to the squad once he has served his suspension," said Ruddock.
"I've only named three out-and-out locks at the moment with the added option of Michael Owen as cover in that department.
"Having invested heavily in Ian in the autumn and seeing him play so well for his region against Leicester in particular, we are keen to get him back on board as soon as possible.
"Henson has played less rugby and he needs to prove himself in his potential outing for the Ospreys on February 17, but the door is certainly open for him to also make a return."
Grand Slam winners Gethin Jenkins, Hal Luscombe and Dafydd Jones are back following their injury problems while Chris Horsman, Brent Cockbain, Ryan Jones, Tom Shanklin and Kevin Morgan have been ruled out for the entire tournament.
Wales squad for the 2006 Six Nations:
Duncan Jones (Ospreys), John Yapp (Cardiff Blues), Adam Jones (Ospreys), Gethin Jenkins (Cardiff Blues), Mefin Davies (Gloucester Rugby), Rhys Thomas (Cardiff Blues), Matthew Rees (Llanelli Scarlets), Ian Gough (Newport Gwent Dragons), Robert Sidoli (Cardiff Blues), Jonathan Thomas (Ospreys), Michael Owen (Newport Gwent Dragons), Gareth Delve (Bath Rugby), Dafydd Jones (Llanelli Scarlets), Alix Popham (Llanelli Scarlets), Martyn Williams (Cardiff Blues), Colin Charvis (Newcastle Falcons), Dwayne Peel (Llanelli Scarlets), Gareth Cooper (Newport Gwent Dragons), Michael Phillips (Cardiff Blues), Stephen Jones (ASM Clermont Auvergne), Nicky Robinson (Cardiff Blues), Shane Williams (Ospreys), Mark Jones (Llanelli Scarlets), Dafydd James (Llanelli Scarlets), Lee Byrne (Llanelli Scarlets), Ceri Sweeney (Newport Gwent Dragons), Hal Luscombe (Newport Gwent Dragons), Matthew Watkins (Llanelli Scarlets), Barry Davies (Llanelli Scarlets), Gareth Thomas (Toulouse - Captain)