Australia legend Glenn McGrath has questioned whether England bowler James Anderson is nearing the end of his career in Test cricket.
The 31-year-old has taken just 12 wickets in the current Ashes series at an average of 47.71, just two years on from claiming 24 victims in a 3-1 win Down Under.
McGrath, who took 563 wickets in 124 Test matches, said that the Lancashire seamer may be finding it difficult to get the Kookaburra ball to react in the same way that the Duke ball does in England.
"Anderson has been a little bit disappointing," the 43-year-old told Sky Sports News. "I've got a lot of respect for him and I think he's a great bowler. He had a very good series last time out here and I thought he had learned to bowl with the Kookaburra, but in this series he's seemed tired and flat. It has been tough.
"I don't know if he had a big workload going into this series or whether it's just because the ball hasn't swung and he doesn't know how to take wickets. When it's swinging he's one of the best bowlers in the world, without a doubt. Time will tell where he's at when he goes back to England.
"If he can lift himself when he gets a Duke ball, which he loves bowling with, and bowl well then he's fine otherwise - who knows - he may be towards the end of his career."
The tourists are 4-0 down and up against it in the fifth Test match in Sydney.