Westwood started in Friday's 2-1 win over Kazakhstan but has been allowed to return to Sunderland early as Giovanni Trapattoni looks to name an experimental line-up for the game in London.
Henderson, back-up to Jussi Jaaskelainen at Upton Park, has not won an international cap for the Republic but was named on the bench for February's friendly draw against Czech Republic.
Trapattoni confirmed on Sunday that Millwall stopper David Forde will start in goal so 24-year-old Henderson is likely to be among the substitutes on Tuesday night. Trapattoni also has Motherwell keeper Darren Randolph available to him.
The Italian has already allowed Robbie Keane, Darren O'Dea, John O'Shea, Jon Walters and Glenn Whelan to return to their clubs following Friday's fortuitous victory in Astana.