Ed Cowan's place in Australia's Test side may go on the line this week after chief selector John Inverarity revealed David Warner was struggling to be fit for the first Test against India.

On the same day Shane Watson made an impressive 84 at the top of the order in a tour match against India A, Inverarity confirmed Warner was struggling to overcome a thumb injury before the first Test, which starts in Chennai on Friday.

Warner's injury opens the door for Watson to play as an opener, which could be bad news for Cowan.

If Watson continues his good form and Cowan fails to make runs in Chennai, the left-hander would be vulnerable when Warner returns for the second Test in Hyderabad.

"There is some concern with David because he hasn't been able to practice," Inverarity told ABC Radio.

"David's thumb has improved in the last couple of days, he wasn't fit enough to play in this game (against India A), he had some throw-downs yesterday with a cricket ball, and we're hoping his fitness improves a great deal in the next couple of days so he comes into contention.

"We won't make a decision on that until a few days out from the Test."

Watson hasn't opened in Test cricket since November 2011 and was slotted into the middle order when he returned from injury during the Australian summer.

The 31-year-old, who has recently given up bowling to focus on his batting, has repeatedly expressed his desire to open the batting in all forms of cricket.

He averages 43.67 in 24 Tests as an opener, including his only two Test centuries.

On Sunday, Watson said he was hopeful Warner would be fit for the first Test and expected to bat at No.4.

"Initially in the first Test anyway, it depends on whether Dave Warner will be fit," Watson said.

"Everyone has their fingers crossed that he'll be fit to play and if he is fit, I'm not sure but I think I'll bat at four.

"The selectors and Michael (captain/selector Michael Clarke) and the coach (Mickey Arthur) haven't really mentioned either way so far about where I'm going to bat.

"I certainly do love opening the batting. It is a lot of fun to be able to open, in any conditions really.

"I know I've got the game plan ... to hopefully have some success batting at number four if that's the case."

Cowan has been in solid form in Australia's tour matches in India, posting scores of 58 and 40.

The Tasmania batsman has just one Test hundred to his name from 13 Tests, averaging 32.81.

Should Warner be ruled out and Watson open the batting, Usman Khawaja is certain to make his return to the Test squad in the middle order after 14 months in the wilderness.

More from 7Sport