England have retained 17 players for the rest of the training week at Pennyhill Park with four Leicester Tigers players among those being released back to their Aviva Premiership clubs.Tom Croft, Graham Kitchener, Geoff Parling and Tom Youngs are to return to Oval Park this evening while Tigers teammates Dan Cole and Ben Youngs are among the players to remain in camp.   England’s starting XV from the game against Italy along with Billy Twelvetrees (Gloucester Rugby) and Jack Nowell (Exeter Chiefs) will train on Wednesday and Thursday before the squad re-assembles on Monday, February 23.   In addition, Manusamoa Tuilagi and Joe Launchbury (Wasps) will be with the squad to continue their rehabilitation this week.   England Head Coach Stuart Lancaster said: “We will release some players back to their clubs this evening as it will be a good opportunity for them to play for their clubs on a big Aviva Premiership weekend and before we get together ahead of the Ireland training week.   “Mike Brown is in in the early days of the graduated return to play protocol and will not be training this week. Geoff Parling, Tom Wood and Courtney Lawes will be released back to their clubs for further assessment and treatment with a view to them resuming training with us next week.”   Players retained for Wednesday and Thursday Dave Attwood (Bath Rugby) Mike Brown (Harlequins) Luther Burrell (Northampton Saints) Dan Cole (Leicester Tigers) George Ford (Bath Rugby) Dylan Hartley (Northampton Saints) James Haskell (Wasps) Jonathan Joseph (Bath Rugby) George Kruis (Saracens) Joe Marler (Harlequins) Jonny May (Gloucester Rugby) Jack Nowell (Exeter Chiefs) Chris Robshaw (Harlequins) Billy Twelvetrees (Gloucester Rugby) Billy Vunipola (Saracens)    Anthony Watson (Bath Rugby) Ben Youngs (Leicester Tigers)   Retained for rehabilitation Joe Launchbury (Wasps) Manusamoa Tuilagi (Leicester Tigers)   Players released to Aviva Premiership clubs Brad Barritt (Saracens) Kieran Brookes (Newcastle Falcons) Danny Cipriani  (Sale Sharks) Calum Clark (Northampton Saints) Alex Corbisiero (Northampton Saints) Nick Easter (Harlequins) Kyle Eastmond (Bath Rugby) Danny Care (Harlequins) Tom Croft (Leicester Tigers) Alex Goode (Saracens) Courtney Lawes (Northampton Saints) Stephen Myler (Northampton Saints) Geoff Parling (Leicester Tigers) Mako Vunipola (Saracens) Richard Wigglesworth (Saracens) Tom Wood (Northampton Saints) Tom Youngs (Leicester Tigers)