Johnson's experience key in young side

Australia's coach Darren Lehmann admits he has no idea how long the team will have Mitchell Johnson, but he believes there are enough good young fast bowlers who can step up whenever Johnson retires. However, Lehmann hopes that Johnson, 34, will be around for some time yet, given the experience and leadership he brings to the attack.

During the first Test against New Zealand at the Gabba, Johnson moved level with Brett Lee on Australia's all-time Test wicket tally, at equal fourth on 310 wickets. Notably, he and fellow left-armer Mitchell Starc worked effectively together, especially when they rattled New Zealand's batsmen during a five-over spell late on the second day.

It was Australia's first Test since the end of the Ashes, and Johnson has previously said that he considered retiring along with Michael Clarke, Shane Watson, Chris Rogers and Brad Haddin after the England tour. However, he decided he still had the desire to play on, and Lehmann said he had no inkling of how long Johnson might stick around.

"He's a pretty private person, Mitch," Lehmann said. "He's opening up a bit now, we've got him in the leadership group so he has to speak a bit more now which is always pleasing. But he looks keen as mustard, and he really wants to do well. Whatever he decides, he decides, but from our point of view he wants to play cricket for Australia, so we want him to play well and get wickets.

"We love his experience and what he brings to the table; he can turn a game very much like he did in that spell with Mitchell Starc in that first innings, where they lost four in 20 balls. So that's great for us. At the end of the day we've got some good depth coming through so I'm not too worried about our fast-bowling department to be honest."

Johnson was to be rested from Australia's Test tour of Bangladesh in October, which was ultimately cancelled, and he also sat out of the start of the Matador Cup. During the Gabba Test he opened up further about his post-Ashes ponderings, telling ABC Grandstand radio that he needed the time at home to confirm in his own mind that he wanted to go on.

"The six-week period I had at home was quite difficult, to be honest," Johnson said. "I wasn't sure if I wanted to play or not. I played the Matador Cup games and the Shield game and I started to get a bit of fire in the belly. I really wanted to see how I was going to feel out here. It's so great to be out playing in front of people.

"I think that's something that when I do retire I'll miss. I remember standing out in the last Test in England at The Oval and thinking what Bucky [Rogers] and Michael were going to be thinking with their last couple of deliveries, what's the feeling going through them, and I started to feel that a little bit as well. But I'm really ready for this summer now. I feel like getting out there and bowling. I am committed and raring."

After the pre-Ashes retirement of Ryan Harris, Johnson now finds himself very much the old man of Australia's attack, and with five further Tests coming up this home summer against New Zealand and West Indies, he could begin to edge towards Dennis Lillee's mark of 355 Test wickets. However, more than personal milestones, Johnson is concerned with helping the developing side.

"I think it's a really important period for me around this squad with a lot of young guys in there, Smithy being a young captain, I feel like I can help out in a lot of ways," Johnson said. "As long as I'm committed to it and want to play, I'll be here for the summer and trying to help out as much as I can."

Whether Johnson - or for that matter Starc or Josh Hazlewood - can play all six Tests of Australia's home summer remains to be seen, and Peter Siddle has again joined the squad in Perth ahead of the second Test against New Zealand after being named 12th man at the Gabba. Lehmann said there was no reason the same attack could play all Tests, but it would be dependent on workload and fitness.

"We'll look at all those sort of options," Lehmann said. "It'll get down to how much bowling I suppose, how long Test matches go for. Again, we'll just go with the simple rule, if they're not 100%, they don't play. If they're 100%, they're fine, good to go. And sometimes 100% might be sore but okay, if that makes sense."