A tweak to his delivery stride, regular first-class game time, and a bit of growing up has put Wayne Parnell in prime position to occupy South Africa's No.7 Test spot, according to his franchise coach Piet Botha. Parnell is one of two all-rounders in the squad to face Australia, and Botha believes Parnell's pace could give him the edge over Ryan McLaren.

"He is definitely ready for Test cricket again. In South African conditions, where the wickets are a little bouncier, he will be a handful," Botha, the Warriors coach told ESPNcricinfo. "He is a little bit older now, he's played a little bit more cricket and he backs himself in tough situations."

It has been four years since Parnell made his Test debut for South Africa as a 20-year-old with dreams to match his promise. He had played nine ODIs before that, with two five-wicket hauls. He also featured in eight Twenty20 internationals, including six in the 2012 World T20 where the seven wickets he took in two games against England and West Indies remain some of South Africa's finest performances at major competitions.

His promotion to play in whites had then seemed a little premature - he had only played nine franchise first-class matches, six three-day provincial games and five division two county games at that point - but South Africa were willing to gamble on his talent. They were searching for a third prong to complete the Dale Steyn-Morne Morkel duo and thought a left-armer would be a good option.

Parnell played three Tests- two in India- and took five wickets, but that was the end of the experiment. The talk around the traps was that the team management wanted him to experience a full season of first-class franchise cricket. But before that could happen, Parnell suffered a severe groin injury in May that year.

Recovery was slow, relapses were frequent and his constant yo-yoing in and out of the limited-overs sides meant that the chance for a prolonged four-day run was elusive. "There was a period of time where he just wasn't playing first-class cricket and that was a problem. The injury didn't help because it plays on a players' mind, they are are never 100% mentally there," Botha said. "He always had the skills to play but he just wasn't getting the game time."

Two seasons ago, in the 2011/12 summer, Parnell played just three matches for the Warriors. Last season, he played five and in the four rounds of the domestic competition completed this year, he has appeared in only one. It was an important one though, as he took eight wickets in the match to give his team a big win.

Parnell also found an opportunity with South Africa A and made an impact there as well. He played both unofficial Tests against Sri Lanka A in the winter of 2012, and was the joint second-highest wicket-taker. Last winter, he played both the games against India A. He was under the watch of people close to the South African team, such as former bowling coach Vincent Barnes, and subsequently improved his performances. Parnell was bowling quickly and his batting, something he was always capable of, was developing.

"He has always had the ability to bowl 145kph plus and if the technical things are all right, he could even bowl quicker than that," Botha said. So it made sense to focus on the adjustments. Botha concentrated on what he could do to ensure Parnell did not just bowl speedily on occasion, but could do it consistently. For that to happen, he had to ask Parnell to change one aspect of his delivery stride.

"Wayne used to have quite a long stride and he would end up blocking himself off, so we worked on getting it a little shorter," Botha explained. "By doing that, he would be bowling a lot from over the top, rather than with his arm side-on, and so could bowl at maximum pace."

It sounds like a minor change, and it was, but it still required time in the nets to perfect the action. That was important in fine-tuning Parnell's work ethic, something he has now become an expert at. "He puts in a lot of extra work these days," Botha said. "He's very professional about the way he goes about things."

The rewards of all the long hours he spent in training are not limited to his bowling. Parnell averaged 48.33 in List A cricket in this season's One-Day cup, scored a century and even opened the batting for the Warriors. His 91 against India A showed he could be more than a white-ball bludgeoner, and Botha believes this can also translate to the Test level.

"What he learned is that when he takes his time to get in, he can really build an innings," Botha said. "When guys come in down the order, sometimes they fall into the trap of thinking they have to score quickly and they end up getting out early. But Wayne has proved if he gives himself a bit of time, he can get runs."

The patience required to play himself in has come with age. "He has grown up a bit," Botha said "But that comes the more you play and now we can see it in Wayne, he's more mature. He's ready for Test cricket again."

The McLaren camp will disagree, citing greater experience and better numbers as the reason their man should fill the gap left by Jacques Kallis. Although both McLaren and Parnell have been international cricketers for five years, McLaren is six years older, has a higher first-class batting average and a lower first-class bowling one.

What he does not have, though, is the gas to send down delivers at close to 150kph from an awkward angle. "Wayne is unique, not just because he is left-armer so he has the advantage of the angle but because he is so quick," Botha said. Because this series has been dubbed a battle of the bowling attacks and pace is expected to play a big role, Parnell is a safe bet to feature heavily in it.

Firdose Moonda is ESPNcricinfo's South Africa correspondent