Lions coach Warren Gatland admits he faces a nervous couple of weeks as many of his squad contest domestic and European cup finals.
And Gatland revealed that those not involved in the finals will have a "big advantage" as they will play in the first match of the tour against the Barbarians in Hong Kong - and therefore have a head start in the race for a Test place.
The 37-man squad gathered in London on Monday for medicals, and to be measured up for their tour suits.
It is the first time the squad has assembled, but many of his players will be returning to Ulster, Leinster, Leicester and Northampton to prepare for domestic and European cup finals.
Gatland says those men will be playing catch-up with their fellow tourists when they return to the squad - but he insists they should not hold back and try to avoid injury when they play in their respective finals.
Gatland said: "The first three-and-a-half weeks will be about preparation for the first Test. The players that prepare for that first game (in Hong Kong) are going to have the biggest advantage on tour.
"They are the players not involved in the finals so they are going to have the best preparation in the next couple of weeks. The players coming back from finals are going to be at a disadvantage because of their lack of preparation time.
"So the team that plays the Barbarians should be in reasonable shape in terms of their preparations in the next couple of weeks."
Gatland admits he is keeping his fingers crossed that his players involved in the Aviva Premiership final (Leicester v Northampton), RaboDirect PRO12 final (Leinster v Ulster) and Amlin Challenge Cup final (Leinster v Stade Francais) come though unscathed.
But he warned those involved that they should not hold back in a bid to avoid injury.
"It's tough for the players in terms of they know a few days after a big game they are on the plane," he said.
"There's a bit of trepidation about not picking up injuries. But if you go in with that attitude and try and look after yourself there is more chance of picking up an injury.
"So the advice to those players is to go hell for leather. It should be a good battle between two forward packs in the (Aviva) final."
"You watch them hoping to see good quality rugby and hoping that those players don't pick up an injuries but in the back of your mind you have to be prepared for that."
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