Australian fast bowler Mitchell Johnson has admitted his struggles with the mental side of professional cricket is what led to his demise in form.

The 30-year-old was one of cricket's most feared bowlers just three years ago, but a series of bad performances for the Baggy Greens has now left his international career in doubt.

"As soon as I get too much information, I don't think it helps me. It's hard when you have a lot of people coming in and telling you what you should and shouldn't be doing," Johnson admitted.

"That's what happens at the elite level. You can get bombarded with people's thoughts and ideas. It's how you deal with it and I didn't deal with it. I started changing things for no reason.

"I'm not blaming anyone, it's my fault. I need to improve the mental side of things and do what I know works for me."

The left-armer is now set to make his Indian Premier League debut this year after being signed by the Mumbai Indians, while he has also admitted he is keen to join English county Glamorgan for their domestic Twenty20 season.

"I'm interested," he said.

"I'm just waiting for a call from them."