Marcus Smith and Alex Mitchell have returned to the England squad ahead of Saturday's Guinness Six Nations clash with Ireland.Harlequins fly-half Smith is yet to feature in this year’s championship due to a calf issue, while Northampton scrum-half Mitchell twisted his knee in training after starting the victories over Italy and Wales.The pair linked up with head coach Steve Borthwick’s group last week for a three-day training camp in York ahead of the final two rounds of the Six Nations, and were on Sunday evening named in a 36-man squad to face Grand Slam-chasing Ireland at Twickenham.Exeter wing Immanuel Feyi-Waboso, who scored a try as a replacement in Saturday’s 30-21 Calcutta Cup loss to Scotland, has also been included after missing the training camp due to having a medical exam at Exeter University which had to be completed face to face.England, who must beat Andy Farrell’s reigning champions to remain in title contention, conclude the tournament against France in Lyon on March 16.