In-form Wasps back row Alfie Barbeary is one of six uncapped players in England's 36-man Six Nations squad.
The 21-year-old has scored four tries in seven games for his club this season after returning from injury.
Bath fly-half Orlando Bailey, 20, and London Irish full-back Ollie Hassell-Collins, 23, are also included.
Centre Manu Tuilagi, who is yet to make his comeback from a hamstring injury, is left out while there is also no space for back row Sam Underhill.
However captain Owen Farrell is included despite not playing since suffering an ankle injury in the win against Australia in November.
Fellow Saracens player Jamie George is one of the hookers - having initially been left out of the Autumn Internationals squad - after he returned from a knee injury ahead of schedule.
But fly-half George Ford, who has steered Leicester to the top of the Premiership, and Saracens back Elliot Daly, who has been short of game time, are left out.
Mako and Billy Vunipola, mainstays of the team that reached the 2019 Rugby World Cup, are omitted once again.
Harlequins centre Luke Northmore, Leicester forward Ollie Chessum and Northampton full-back Tommy Freeman complete the set of uncapped players.
"Selecting this squad has been a difficult task, we've got plenty of good young players coming through and some of our more experienced are rediscovering their best form," said head coach Eddie Jones.
"We think this 36 for the first training week reflects a good balance of that experience and up-and-coming talent."
England's Six Nations squad
Forwards
Alfie Barbeary, Jamie Blamire, Ollie Chessum, Luke Cowan-Dickie, Tom Curry, Alex Dombrandt, Charlie Ewels, Ellis Genge, Jamie George, Joe Heyes, Jonny Hill, Maro Itoje, Courtney Lawes, Lewis Ludlam, Joe Marler, Bevan Rodd, Sam Simmonds, Kyle Sinckler, Will Stuart
Backs
Mark Atkinson, Orlando Bailey, Owen Farrell, Tommy Freeman, George Furbank, Ollie Hassell-Collins, Max Malins, Joe Marchant, Jonny May, Luke Northmore, Jack Nowell, Raffi Quirke, Harry Randall, Henry Slade, Marcus Smith, Freddie Steward, Ben Youngs