Brian O'Driscoll will captain the British and Irish Lions against Western Force on Wednesday, but his fellow Ireland international Rob Kearney has emerged as an early tour injury concern.
Leinster full-back Kearney has a hamstring problem and Lions head coach Warren Gatland is planning to keep a close eye on his progress.
Gatland said: "He is a little bit of a concern for us at the moment, to be honest.
"He's got a grade one tear and we are going to see how he responds, so we've got to be potentially prepared that that hamstring might not heal as quickly as we would like.
"We want to give him some time. We scanned him in Hong Kong, it came back as a grade one tear and the medics have put in a plan for the next week or so.
"We feel like we've got cover at the moment with Leigh Halfpenny and Stuart Hogg, and obviously Sean Maitland has played quite a lot at full-back as well.
"We will see how Rob progresses. There have been some markers put in place. If we can hit those in the right timescale we can hopefully bring him back. But it looks a little bit concerning at this stage."
O'Driscoll, the 2005 Lions tour captain in New Zealand whose trip was cruelly cut short when he was spear-tackled out of the first Test, leads a powerful side containing eight Irishmen, four Welsh and three English.
As expected, there are 15 changes from the side that crushed the Barbarians 59-8 in hot and humid Hong Kong two days ago, with Halfpenny, wing Tommy Bowe, centre Manu Tuilagi, hooker Rory Best and flanker Tom Croft among those who make their first tour starts.
Four of the side that started at Hong Kong Stadium - prop Mako Vunipola, number eight Toby Faletau, fly-half Owen Farrell and wing Sean Maitland - are on bench duty this time around.
Tour skipper Sam Warburton is kept waiting for his first appearance after careful management of a knee injury, but that moment looks set to arrive against Queensland Reds in Brisbane next Saturday.
"We've said that we were going to keep him (Warburton) out of training for about five days after he had that injection," Gatland said.
"He has been coming back and doing some of his own training, so the five days was before he was ready to start full contact.
"We are just trying to make sure that everyone is getting the same opportunity, and we want the whole team training together that is taking the field.
"It's only fair to the other players around him that they get that chance and so Sam, after Wednesday, will come and train with us over the next couple of days with the non-23 and then put himself into contention for selection for Saturday."
O'Driscoll is now on his fourth Lions tour and he has returned to Australia 12 years after making a scintillating contribution, including an unforgettable solo try during the first Test victory over the Wallabies in Brisbane.
"Yes, it was a fantastic feeling," he said. "I was a young guy just starting out on my career. It was all very new to me.
"I suppose I was just trying to go with the flow and feel my way into things, and pulling on the jersey for the first time was a very, very special moment and something I will always remember.
"But it is one thing pulling the jersey on, it's another thing winning with the Lions, and that is the mentality we've got across the squad.
"It is very exciting. I haven't lost any of the buzz for the feeling of being involved with the British and Irish Lions. It is a very, very special place to be.
"Now that we've finally arrived in Australia the tour kind of feels it has truly begun now we have landed on Australian soil.
"We were pleased with how we started (against the Barbarians) but we've got to continue building, working hard at training and when we get to games trying to build a bit of a ruthlessness about our mentality and our performance."
British and Irish Lions team to play Western Force on Wednesday: L Halfpenny (Wales); T Bowe (Ireland), B O'Driscoll (Ireland, capt), M Tuilagi (England), G North (Wales); J Sexton (Ireland), C Murray (Ireland); C Healy (Ireland), R Best (Ireland), D Cole (England), A-W Jones (Wales), I Evans (Wales), T Croft (England), S O'Brien (Ireland), J Heaslip (Ireland).
Replacements: T Youngs (England), M Vunipola (England), M Stevens (England), G Parling (England), T Faletau (Wales), B Youngs (England), O Farrell (England), S Maitland (Scotland).