Henshaw, 23, is set to see a consultant in Dublin over the knee injury that ended his tour in last Saturday’s 32-26 second Test defeat to the Springboks.
The Leinster-bound Connacht back headed home on Sunday as his team-mates left Johannesburg for Port Elizabeth to prepare for the winner-takes-all Test.
Schmidt said he would not call in anyone from Ireland’s standby list to replace Henshaw, with Luke Marshall or Jared Payne the most likely candidates from the existing squad to slot in at outside-centre.
If Payne were to be switched from full-back to number 13, his Ulster team-mate Marshall would most likely start at inside-centre, with Connacht’s Tiernan O’Halloran moving in at 15 following his Test debut off the bench last weekend.
Keeping Payne at full-back, alternatively, could see Marshall in at 13 to partner last week’s starting 12 Stuart Olding in another all-Ulster midfield.
Explaining the extent of Henshaw’s injury would be unclear for “a week or two”, Schmidt added: “It’s unfortunate, especially for Robbie who was in great form.
“We think we have enough to cover the position this week. We’ve got Jared who can come forward and Tiernan can go to the back, or we’ve got Luke who can go back in at No 13 and he’s played with Stu before. Keith Earls has also played in the midfield for us during the World Cup, so we have a few options there.”
Midfield may not be the only area in the Ireland XV where Schmidt makes changes for the Nelson Mandela Bay Stadium showdown. Last Saturday, he kept his replacement backs on the bench until the final few minutes as Ireland surrendered a 26-10 advantage they’d held at the hour mark.
“We’ve got a tired group on the back of our performance on Saturday, which I thought was a full and quite draining effort. At the same time, it’s hard to take anything away from players who are giving it their best effort when they’ve run out of legs and they’re still trying to find their way into the rhythm of the game.
“But it’s one of those things now that we’ll hopefully have a couple of fresh bodies this week and that’ll help boost the level of energy.”
Aside from Henshaw, team manager Mick Kearney reported the 31 remaining players on tour were all fit and available to train this morning after the squad yesterday completed its recovery from Saturday’s gruelling match, Today will begin the countdown to Ireland’s 17th and final Test of a season which began last June 29 when the players went into pre-World Cup training camp. Yet there is plenty still at stake with a historic first series victory in South Africa on the line thanks to the remarkable opening Test win in Cape Town, Ireland’s first such win here.
Schmidt is aware that a major achievement is in the offing and is determined the Springboks should not feel the benefits of their powerful finish to last Saturday’s Ellis Park contest when they scored 22 points in the final 20 minutes.
“It couldn’t be much more finely balanced and as disappointed as we are with the last 20 minutes of last weekend, what people thought might happen on this tour and what the players put on to the pitch are I think two different things.
“I’d love to see that continue on Saturday, I know the Springboks have got some rhythm and the power-play that they demonstrated in that last 20 minutes will put them on the front-foot. We’d love to turn that around and surprise everyone again.”