The Lions will wait for this weekend's round of matches before finalising the replacements for the injured Tomás O'Leary and Tom Shanklin, as well as drawing up a contingency plan should Alan Quinlan land a suspension next week when he answers a charge of ­making ­contact with an opponent's eyes.

The Harlequins scrum-half, Danny Care, is the favourite to replace O'Leary, who broke his ankle playing for Munster three days after the Lions squad was named last month. Quins face London Irish at the Stoop tomorrow in a Premiership play-off semi-final with their wing Ugo Monye one of 17 of the 34 Lions, excluding Quinlan and the two injured backs, in action this weekend.

Shanklin was injured last Wednesday four minutes from time after helping ­Cardiff Blues defeat Newport Gwent Dragons. He was one of six Blues in the Lions squad and when the old Cardiff club had the same number chosen by the Lions for the 1968 tour to South Africa, including the current manager, Gerald Davies, they immediately rested them.

The game was amateur then with league rugby a generation away and knock-out cup still a matter for debate. The Blues still have to qualify for next season's tournament, with the lowest-placed Welsh region in the ­Magners League going into a play-off against an Italian club on 29 May, the day before the start of the Lions tour.

The Blues head coach, David Young, played three of his Lions against the ­Dragons, with the other three facing Munster tomorrow. "It is very difficult," Young said. "It goes without saying that we want the players on the Lions trip and we are devastated that Tom cannot go, but if I rest them all and we do not qualify for the Heineken Cup, I will be in the firing line. Players are going to pick up bumps and you just cannot say that players end their seasons when the Lions announce their squad. Once we are in the Heineken Cup, my Lions will concentrate on the tour."

The Lions captain, Paul O'Connell, has been rested by Munster for the trip to the Arms Park after sitting out a ­training ­session this week. "It was nothing serious, but Paul has a big summer coming up and we felt it was not in his best interests to play," said Shaun Payne, the Munster team manager. "We are confident he will be involved in our final game of the season against Ospreys next weekend."

The Lions will be monitoring the first of tomorrow's Premiership semi-finals between Leicester and Bath. The Tigers have two contenders to replace Quinlan, should the need arise following the 34-year-old's citing after the Heineken Cup semi-final between Munster and Leinster, in Tom Croft and Lewis Moody. Croft was singled out by the tourists as being particularly unfortunate not to make the 37, while the fit-again Moody would better replicate the abrasive Quinlan.

The Lions are running out of time with the squad gathering for a week's bonding and training in Bagshot on 18 May. Those involved in the following weekend's Heineken Cup final between Leinster and Leicester will leave after the first day. That number is currently five, but it could rise with the Ireland centre, Gordon D'Arcy, one of the candidates to replace Shanklin, while Croft and Moody would be in the frame should Quinlan receive a ban that would rule him out of at least part of the tour.

Lions in waiting

Centre: Gordon D'Arcy (Leinster), Mike Tindall (England), Josh Lewsey (England)

Outside chance: Delon Armitage (England)

Scrum-half: Danny Care (England), Chris Cusiter (Scotland), Dwayne Peel (Wales)

Long shot: Peter Stringer (Ireland)

Blind-side flanker: Tom Croft (England), Lewis Moody (England), Ryan Jones (Wales).

Outside bet: Jason White (Scotland)