Sweeney crosses for try against former club Boxing Day 2008
Huw Evans PA
Dragons Coach Paul Turner confirms fly half Jason Tovey and lock Luke Charteris fail late fitness tests, but centre Ashley Smith returns.
Joe Bearman, Grant Webb, Aled Brew, Pat Palmer and Matthew Watkins are also out. Those injured Dragons players join lock Adam Jones and flanker Dan Lydiate - who are out for the season - plus Danny Lee on the sidelines.
James Arlidge starts at outside-half as Tovey has failed to recover from a knock sustained in last weekend's win over Edinburgh. Bearman is replaced in the back-row by Newport RFC captain Andrew Coombs.
"I'm really hoping it's going to be a high energy game with a lot of movement of the ball and two teams trying to take each other on," said Dragons backs coach Darren Edwards.
"They've got quality players that we will have to stop and to do that, we will have to be in their faces. We are developing a style of play and it is attack."
Newport Gwent Dragons: Martyn Thomas; Will Harries, Tom Riley, Ashley Smith, Richard Fussell; James Arlidge, Wayne Evans; Hugh Gustafson, Tom Willis (capt), Ben Castle, Rob Sidoli, Hoani MacDonald, Andrew Coombs, Gavin Thomas, Toby Faletau.
Replacements: Lloyd Burns, Nigel Hall, Lewis Evans, James Harris, Rhodri Gomer Davies, Adam Hughes, Alex Walker.
Cardiff Blues travel to Myreside on Friday to take on Edinburgh Rugby in a crucial Guinness PRO12 clash, and with Wales facing Scotland in the RBS 6 Nations at BT Murrayfield on Saturday, it promises to be a weekend of non-stop rugby action at the Scottish capital. Here are some useful advice to Cardiff Blues travelling supporters.
To celebrate the opening of the newly refurbished Guinness PRO12 Pack Bar, the world famous Irish brewer will be offering supporters free pints of the black stuff ahead of Saturday's clash with Ulster.
'TACKLE' - the first-ever joint community rugby initiative between the four professional teams in Wales has been launched (today Weds 19th October) bringing an inspiring new rugby education programme to young people in Communities First areas. Partners in the project were joined by Wales' star rugby internationals Sam Warburton (Cardiff Blues), Alun Wyn Jones (Ospreys), Gareth Davies (Scarlets) and Hallam Amos (Newport Gwent Dragons), for the launch at Aberdare Community School.
The Welsh Rugby Union, together with Pro Rugby Wales, has secured significantly improved insurance cover for all registered players, coaches and referees at each of its member clubs and regions at reduced costs -working with Aon, one of the world's largest insurance brokers and risk advisors.