Wales flanker Sam Warburton, the Lions' fifth-youngest skipper, could miss out on Saturday's opener against the Barbarians due to a puffy knee.
Lions head coach Warren Gatland will tomorrow announce a starting line-up dominated by Wales players prior to nine games in Australia.
The match-day 23 on Saturday is set to comprise those players involved at training camps in Wales and Ireland during the past fortnight.
More than a dozen more who featured in last Saturday's play-off finals will gain their opportunities against Western Force and Queensland Reds next week.