New Delhi: India's Test squad was struck with another injury blow ahead of the gruelling cricket tour of Australia as pacer Varun Aaron was replaced by Vinay Kumar owing to a back problem.

Aaron, whose injury was detected on Thursday, has become the second first-choice pacer after Praveen Kumar to be replaced from the squad due to injury.

The 22-year-old Aaron has got "stress reaction on the back" which he sustained during the ongoing ODI series against the West Indies. Aaron was left out of the ODI team after playing the first two matches at Cuttack and Visakhapatnam.

Praveen picked up a rib injury during a Ranji Trophy match and was replaced by Abhimanyu Mithun in the squad which has been picked for four Tests against Australia starting December 26 in Melbourne.

The 27-year-old Vinay has not played any Test cricket so far. His nascent career is just 15-ODI old and the Karnataka bowler has taken 16 wickets so far. He has also played 5 Twenty20 matches picking up five wickets.

Though Vinay was not a part of the squad for the World Cup, he has been the most experienced of the quick bowlers in the side for the ongoing home series against West Indies, until Irfan Pathan was included for the final two one-dayers.

He has been a consistent performer in first-class cricket for several seasons. He was the second highest wicket-taker in the Ranji Trophy in 2007-08, a feat he repeated two years later when he spearheaded Karnataka's attack during their run to the final.

Aaron, considered a promising name in the Indian pace reserve, had played just one Test picking up three wickets in it.