Steve Borthwick believes James Haskell's experience will be vital for the British and Irish Lions during their tour of New Zealand, which starts on Saturday.
Flanker Haskell replaced England number eight Billy Vunipola, who pulled out of the squad due to a shoulder injury.
The 32-year-old Wasps player has 75 international caps and has played Super Rugby.
And forwards coach Borthwick believes Haskell will be a crucial asset for Warren Gatland's side, who face their first tour game against Provincial Union on Saturday.
He said: "I'm really disappointed for Billy. As a player, I have worked closely with him and he's worked very hard to develop.
"What we have got in James Haskell is a player with immense experience to join the group at international level, played Super Rugby, played against many of the players we are going to be facing, a great character to have in the group.
"We have a great blend of players, of defenders, carriers, lineout forwards."
Haskell had been named in the England squad to travel to Argentina this summer.
Borthwick added skipper Sam Warburton is fully fit and he has been impressed with the quality of players he is working with.
"We know this is a demanding tour, everyone is preparing accordingly," he added.
"We have a fantastic and exciting group of players. The calibre and competitiveness of the players is brilliant.
"We know we have to work exceptionally hard and play at our best but that's what makes it exciting."
The first Lions Test against the All Blacks is on June 24 in Auckland.