Centre Garry Ringrose has been ruled out of the British & Irish Lions' series-opening test against Australia after failing a concussion test, while hooker Luke Cowan-Dickie is a doubt after a head-knock in the big win over AUNZ on Saturday.
Ireland midfielder Ringrose, who scored a try in the 36-24 win over the ACT Brumbies on Wednesday, was replaced by Huw Jones in the Lions team that thumped the Australia-New Zealand invitational side 48-0 at Adelaide Oval.
"Garry again had a concussion from last week, lingering signs of concussion so he had a headache and unfortunately he failed that," head coach Andy Farrell told Sky.
"That's very sad for Garry but he'll be back within the rest of the series very shortly so that's just the way the game goes."
Centre/fullback Jamie Osborne was called up to the squad as additional training cover during the week.
Cowan-Dickie came off second-best in a tackle against big lock Lukhan Salakaia-Loto before half-time at Adelaide Oval and was carted off the ground.
Farrell said the England hooker was in good spirits but it looked like he had also suffered concussion and another player might need to be brought into the squad.
"He got up straight away as he got off the stretcher and he's back to being his normal self," added Farrell.
"It's unfortunate for him... so we'll see what has to happen on the back of that."
England hooker Jamie George may be among the first in line for a call-up to cover Cowan-Dickie's injury.
Farrell's son Owen, the former England captain, did his chances of selection for the three-match series against the Wallabies no harm with a solid outing against AUNZ after coming off the bench early in the second half to replace Jones.
Farrell had a hand in three of the Lions' five second-half tries and attacked the AUNZ line with vigour.
It was by far the Lions' sharpest performance of the tour and a big improvement after their laboured win over the Brumbies.
They racked up three tries in the opening 21 minutes and defended well to shut out opponents featuring 14 test players.
"I thought it was a good professional performance," said Andy Farrell.
"I suppose when you play these type of games, the type of personnel that you're coming up against, all sorts of things can happen.
"But I thought we played a nice, controlled game of rugby and didn't really let them in the game or get the confidence going."