England's Marcus Trescothick is set to miss Wednesday's first Test in India after flying home for personal reasons.
Trescothick's loss will be a big blow to England in Nagpur
The injury-hit tourists have already called up Alastair Cook and James Anderson, and coach Duncan Fletcher said cover for Trescothick was needed.
"He is a world-class opener. To lose someone like that is a big blow to us. It's another hitch we have to overcome but opens the door for another player.
"Phone calls have been made to get in another batting replacement," he said.
Captain Michael Vaughan says he will open with Andrew Strauss in Nagpur - if the problem with his right knee eases sufficiently.
Vaughan missed the final warm-up game against the Indian Board President's XI and will give himself 48 hours before deciding on his availability.
"I had an injection to ease the trouble on Wednesday, tried the knee in the nets yesterday and still felt it," he explained.
"I'll take part in full practice on Monday and will have more of an idea after that.
"Hopefully I can get it right and give myself a chance. The injections have worked for me in the past."
If Vaughan is ruled out, key all-rounder Andrew Flintoff will captain the side, with promising Essex batsman Cook in line to make his debut as Strauss' partner.
The 21-year-old was drafted in alongside Lancashire seamer Anderson from the England A squad in the Caribbean after injury and illness ravaged the squad.
All-rounder Paul Collingwood and batsman Kevin Pietersen are suffering from sore backs, while seamer Simon Jones has a stomach bug.
But Fletcher is optimistic about the trio saying: "Simon had three really good spells in the nets to try to simulate what he might get out in the middle.
"Collingwood and Pietersen have responded very well and if you had to pick a side for tomorrow they'd be available."
Meanwhile, England have refused to expand on Trescothick's sudden departure, other than saying it is for "a family reason".
The Somerset left-hander considered coming back early from Pakistan in November when his father-in-law was seriously injured falling off a ladder.