England have recalled Nick Easter and Danny Cipriani to their training squad for the opening Six Nations game against Wales, while five British and Irish Lions return after injury.
Easter wins his first call-up since 2011, while Cipriani has not been in a Six Nations squad since 2008.
Lions Alex Corbisero, Dan Cole, Geoff Parling, Tom Youngs and Mako Vunipola are back in the 34-man training squad.
Sam Burgess is included in the second-string Saxons, along with Tom Croft.
Rugby league convert Burgess has only played seven matches since joining Bath earlier this season but has been improving with every performance and was man of the match in the win over Wasps 10 days ago.
|England Six Nations fixtures|
|6 Feb: Wales v England, 20:05 GMT|
|14 Feb: England v Italy, 14:30 GMT|
|1 Mar: Ireland v England, 15:00 GMT|
|14 Mar: England v Scotland, 17:00 GMT|
|21 Mar: England v France, 17:00 GMT|
England play Wales at the Millennium Stadium on 6 February, while the Saxons play the Irish Wolfhounds on 30 January.
Lancaster said Cipriani has "not been far away" from making the squad since he toured with England last summer, when he played his first Tests since 2008, making two impressive cameos off the bench.
The England coach said he felt Northampton's Stephen Myler "had the edge on him" during the autumn Tests, but added: "Since then Danny's improved his game, he's worked hard and we want to create the opportunity for him and Steve to come in to the squad together.
"It's a good chance for Danny to come in and put a marker down."
Lancaster said Easter's situation was "slightly different" as he has not been in England's plans since the coach took over in 2012, but with Gloucester's Ben Morgan out of the tournament through injury and the need to have two specialist number eights in the squad, the time has come to have another look at the Harlequins veteran.
"To be fair Nick has been outstanding for Harlequins and deserves his opportunity to come in and prove that he can replicate that back at international level," explained Lancaster.
"Both are in the mix. In regards to the 10 slot George Ford and Owen Farrell both played extremely well at the weekend but we'll see where we go."
Cipriani, 27, said he was "delighted to have been given the opportunity".
"It's a great chance for me to prove myself and hopefully get a chance to represent my country again," he added.
Former England centre Jeremy Guscott, though, does not think Ciprani will play much of a role during the Six Nations.
Guscott told BBC Radio 5 live: "You have to remember that Owen Farrell has done well for England. He has never let his country down. And George Ford has come in and is playing incredibly well. Cipriani is going to have to play 20 to 30% better to even challenge those two.
"He has played well. He is running the Sale back line incredibly well. But one thing you need at international level is a top-drawer kicker and unfortunately, Danny's percentage success rate is not as good as Farrell's or Ford's. It's 10 or 11% lower."
The training squad will be cut to the match-day 23 on the Monday or Tuesday before the Wales game, with the rest released back to their clubs.
Leicester lock Graham Kitchener replaces Northampton's Courtney Lawes, who has had minor ankle surgery.
In addition to Lawes, Leicester centre Manu Tuilagi was also not considered for the Wales game because of injury, but it is hoped the pair may recover in time to play some part in the tournament.
Full-back Ben Foden (knee) and second rows Joe Launchbury (neck) and Ed Slater (knee) join Morgan in missing the entire Six Nations because of injury.
England senior training squad:
Props: Dan Cole (Leicester Tigers), Alex Corbisiero (Northampton Saints), Joe Marler (Harlequins), Mako Vunipola (Saracens), David Wilson (Bath Rugby); Hookers: Dylan Hartley (Northampton Saints), Tom Youngs (Leicester Tigers); Locks: Dave Attwood (Bath Rugby), Graham Kitchener (Leicester Tigers), George Kruis (Saracens), Geoff Parling (Leicester Tigers); Back-rows: Calum Clark (Northampton Saints), James Haskell (Wasps), Nick Easter (Harlequins), (Wasps), Chris Robshaw (Harlequins, captain), Billy Vunipola (Saracens), Tom Wood (Northampton Saints),
Back three: Mike Brown (Harlequins), Alex Goode (Saracens), Jonny May (Gloucester Rugby), Jack Nowell (Exeter Chiefs), Anthony Watson (Bath Rugby); Centres: Brad Barritt (Saracens), Luther Burrell (Northampton Saints), Kyle Eastmond (Bath Rugby), Jonathan Joseph (Bath Rugby), Billy Twelvetrees (Gloucester Rugby); Fly-halves: Danny Cipriani (Sale Sharks), Owen Farrell (Saracens), George Ford (Bath Rugby), Stephen Myler (Northampton Saints); Scrum-halves: Danny Care (Harlequins), Richard Wigglesworth (Saracens), Ben Youngs (Leicester Tigers).
England Saxons squad:
Props: Kieran Brookes (Newcastle Falcons), Ross Harrison (Sale Sharks), Matt Mullan (Wasps), Henry Thomas (Bath Rugby), Alex Waller (Northampton Saints); Hookers: Luke Cowan-Dickie (Exeter Chiefs), Rob Webber (Bath Rugby), Second rows: Christian Day (Northampton Saints), Matt Garvey (Bath Rugby); Back row: Tom Croft (Leicester Tigers), Dave Ewers (Exeter Chiefs), Maro Itoje (Saracens), Matt Kvesic (Gloucester Rugby), Thomas Waldrom (Exeter Chiefs).
Back three: Chris Ashton (Saracens), Chris Pennell (Worcester Warriors), Marland Yarde (Harlequins), Christian Wade (Wasps); Centres: Sam Burgess (Bath Rugby), Elliot Daly (Wasps); Fly-halves: Ollie Devoto (Bath Rugby), Henry Slade (Exeter Chiefs); Scrum-halves: Lee Dickson (Northampton Saints, captain), Joe Simpson (Wasps).