Dalrymple's Middlesex team-mate Andrew Strauss was confirmed as captain for the remainder of the four-Test series against Pakistan after it was announced Saturday that Flintoff, who missed the drawn opener at Lord's, would require surgery on his injured ankle.
"As we will now be without Andrew Flintoff for an extended period, the selectors have appointed Andrew Strauss as captain for the rest of the Test series against Pakistan," chairman of selectors, David Graveney, said after announcing the squad Sunday.
"A decision on the captaincy of the one-day side for the NatWest Series (also against Pakistan) will be made in due course.
"We are very disappointed to lose Andrew Flintoff as both a player and a captain.
"The medical staff from both Lancashire and England had worked extremely hard to try and help him overcome the injury without recourse to surgery and Andrew himself had done everything that was asked of him.
"His priority now will be to ensure he is fully fit for the Ashes in Australia."
Meanwhile Graveney cast doubt on the prospects of Liam Plunkett, who was in England's XI at Lord's, making it into the team at Old Trafford after the Durham quick sustained a side strain while on county duty.
"We have taken the precaution of including 14 players in the squad for this Test match as Liam Plunkett injured his side playing for Durham against West Indies 'A' and his fitness will need to be re-assessed over the next 48 hours.
"Jamie Dalrymple performed impressively during the NatWest Series (against Sri Lanka, where England were beaten 5-0 in five one-day matches) and his inclusion will give the captain and coach another option when they decide on the starting line-up for this Test match."
Squad: Marcus Trescothick (Somerset), Andrew Strauss (Middlesex, capt), Alastair Cook (Essex), Kevin Pietersen (Hampshire), Paul Collingwood (Durham), Ian Bell (Warwickshire), Geraint Jones (Kent, wkt), Liam Plunkett (Durham), Matthew Hoggard (Yorkshire), Stephen Harmison (Durham), Monty Panesar (Northamptonshire), Jon Lewis (Gloucestershire), Sajid Mahmood (Lancashire), Jamie Dalrymple (Middlesex)