The 26-year-old, who has scored 10 goals in 16 appearances this season, has been out of action since December 15 due to a hamstring injury, but is back in training.
Rangers boss Jimmy Floyd Hasselbaink admitted he is yet to decide whether Austin will be selected in South Yorkshire but is not prepared to risk him.
That will be a boost to the Millers, looking for a fourth successive home win, as Austin bagged two in August's reverse fixture.
Hasselbaink said: “Charlie has only been back training with the group for a week. He is somebody that we can’t take a chance on.
“He was out with a
hamstring injury, and that type of injury can be a big problem.
“We want to make sure
that he is ready. I haven’t made my mind up on whether he’ll feature yet. But
we can’t afford to lose Charlie for another six weeks. We need to make sure he
is ready."
Hasselbaink could quite easily have been in the home dugout for this fixture after the Millers approached his then-club Burton when searching for Steve Evans' replacement in early October.
Instead he is bringing Rangers to New York for the first-ever time and his is still waiting for a first win at the helm as his side have not registered three points since early December.
And Hasselbaink is expecting a stern test.
“It’ll be a big test –
they also create a good atmosphere there," the Dutchman said.
“We have to respect
that. If you don’t, you’ve already lost. We have to respect Rotherham and make
sure that we’re at our best.
“Concentration has to
be right – our organisation has to be right.
“You have to work from
your organisation, and try to work the ball. We want to try and cause problems,
and hopefully score a few goals – without having any against.”
