Carter was superb against Wales in New Zealand's 42-9 first Test win
New Zealand could be without star fly-half Dan Carter when they take on tourists Wales in the second Test at Hamilton on Saturday.
Carter will be named in the All Blacks line-up on Tuesday, but his place will not be confirmed until Thursday.
If unfit, Aaron Cruden, who took over after Carter scored 27 points in his side's 42-9 win in Dunedin, will play.
All Blacks assistant coach Wayne Smith said: "We probably won't be able to make a decision until Thursday."
Full-back Israel Dagg (concussion) and lock Anthony Boric (cheekbone) are even more serious doubts than Carter in the wake of the All Blacks' winning farewell to Carisbrook in Dunedin.
Centre Conrad Smith could also be missing after suffering an eye injury against Wales while wing Joe Rokocoko has a minor knee problem.
Carter pulled up with a tight calf late on by which time he had scored two tries, kicked four conversions and three penalties.
We'll play him if he's right. If he's not right we won't play him
All Blacks assistant coach Wayne Smith on Dan Carter
"He'll have to have a couple of days of modified training," Smith said. "We probably won't be able to make a decision until Thursday on him given the nature of the tightening of the calf.
"It's not actually a calf pull or anything like that, it's just a tightening. But we've got to make sure it's right."
Smith said the possibility of Wales being without their experienced number 10 Stephen Jones (thumb) would play no part in their decision to play Carter.
"We'll play him if he's right. If he's not right we won't play him."
If Carter is ruled out, the spotlight will turn to last year's International Rugby Board's Under-20 player of the year, Cruden.
The 21-year-old Hurricanes pivot has a total of 32 minutes of international rugby under his belt after 25 minutes against a hapless Ireland and the last seven minutes against Wales where he was only denied a maiden Test try by a solid Ryan Jones tackle that bundled him into touch at the corner flag.
"We've brought Aaron in to develop him and he's shown he can just step into a Test match and play, which is promising," said Smith.
Carter's limited involvement at training will also ensure Cruden gets an extended run with the team in the build-up to the Waikato Stadium clash.
"It's actually a good thing giving him a bit more time steering the ship. He hasn't got any problem with that," Smith added.
"He's very composed and he's got the right personality to be ordering people around. But it will be good for him to be in there and have to do that for a few days."
Smith was also coy on whether the likes of Zac Guildford, Piri Weepu, Adam Thomson and Aled de Malmanche would start after having little or no game time during the past two matches.
"The first thing is that we've got to win this Test match - I think that's key," Smith stressed.
"It's all very well talking about things and working on things but at the end of the day we've got to stick it on the track again so we've got to pick the right players to do that."
He also made it clear that a repeat of the first half at Carisbrook would not be tolerated.
The All Blacks lost in the possession and territorial stakes and were put under pressure by some astute kicking from Stephen Jones and the Welsh rush defence.
Although they led 15-9 at the break, Henry's half-time pep talk left his team in no doubt that he expected better - and he got it.
Smith hinted that a lack of "edge" had contributed to the slow start - possibly the result of such a one-sided 66-28 win against the Irish the previous weekend.
"The week before we started really well against Ireland but then there were a lot of players who were unsure, who were anxious and who were going into the unknown and that tends to make you uncomfortable and raises your level of performance quite often," said Smith.
"I don't think there was quite that same feeling last week. This week we've got to ensure that the build-up individually is genuine and the boys that we select really get stuck into it from the start, not just halfway through."