The improved fitness levels of Mohammed Shami. Jasprit Bumrah's outswinger to right-hand batsmen. Also, India's fast-bowling bench strength, and the facilities now available in the country; all these are indicators of Indian fast bowling's great health, according to former pace spearhead Zaheer Khan. Still, Zaheer would like to see Navdeep Saini given a chance in Test cricket.

"The longer format, that's the format that suits Saini," Zaheer told Mumbai Mirror. "Saini has got the pace and consistency in length."

Saini, who was among India's reserves for the World Cup, put his pace and short-ball skills on full display on the tour of Florida and the Caribbean in August. On T20I debut, Saini was on a hat-trick after getting Nicholas Pooran and Shimron Hetmyer off consecutive balls in Lauderhill. He finished that game with figures of 3 for 17, and the Player of the Match award.

In the Test matches that followed, Bumrah was at his lethal best, with 13 wickets in four innings at an average of 9.23, including only the third hat-trick by an Indian in the format. Chief among Bumrah's weapons in this series was the ball that moved away from the right-hand batsmen, and his newfound ability to bowl this delivery consistently makes him all the more potent, Zaheer said.

"I have always said that if he had that outswinger for the right-handers, he will be a nightmare for the batting sides. I am glad that it has happened now," Zaheer said. "He needs to work on his fitness and keep doing the things that have brought him this far. With experience he will keep getting better and better."

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Zaheer said Shami - who had finished third on the Test-wicket charts in the West Indies, taking nine at 17.77 - was reaping the benefits of the work he had put into his fitness. "With Shami we all knew about the wrist position and the upright seam. The only iffy thing was fitness but now he has worked on that."

During the World Cup in England this year, Shami had spoken of how he had worked hard on that aspect of his cricket. Leg issues kept him out for parts of 2016 and 2017, and when he returned for India, it seemed obvious that his fitness levels were down. That phase culminated with him missing out on the Afghanistan Test in Bengaluru in June last year, after failing a fitness test.

"I was heavy after the injury, I used to feel tightness in my knee after long spells, so I knew I had to do something extra if I had to play for a longer time," Shami had said during the World Cup. "I have cut down on my food, I follow a diet and people laugh about it when I tell them that. It's not strict, but I avoid stuff doctors tell me to. I don't eat sweets or bread, it has helped me a lot."

Zaheer said the "hunger" Shami has shown to get to where he is at the moment was commendable. "He has been phenomenal in terms of getting his fitness level up to the standard that is required. This has been a huge plus for him. Ability was always there. Just that some injuries had kept him out for a year. He has come back strongly. A lot of credit has to go to him for how he is managing himself and the hunger that he has shown to come back and play at the top level."

When asked what has made the biggest difference in getting Indian fast bowling to the healthy state it is now in, Zaheer said: "Over the years, the infrastructure has improved. There is this access to better fitness facilities. There are these processes in place like the one at the National Cricket Academy where players are taken care of since Under-14s. There is also a proper passing of knowledge and that is helping in a big way."