On November 14, India's two fastest bowlers were in action, concurrently, in two different games. In Bangalore, Varun Aaron was bowling second-change for India against South Africa, behind Stuart Binny's medium-pace and R Ashwin's offspin. In Nagpur, Umesh Yadav was leading Vidarbha's attack against Rajasthan in the Ranji Trophy.

Both had played the first Test in Mohali. Between them, on a pitch far more suited to spin than their pace, they had bowled 20 overs for the cost of 40 runs, and picked up one wicket. Aaron had taken that wicket, discomfiting Dean Elgar with a short ball in South Africa's second innings and getting him caught off the leading edge.

Perhaps it was that wicket that swayed India into playing Aaron and not Umesh when the second Test rolled around and Ishant Sharma, the leader of their pace attack, returned from suspension. It must have been a hard decision, for Umesh had looked impressive during India's last Test series in Sri Lanka, troubling Angelo Mathews, the opposition's best batsman, with pace and outswing.

In any case, India opted for Aaron at the Chinnaswamy Stadium, and released Umesh to play for his Ranji side.

Aaron came on in the 11th over of South Africa's innings, with the scorecard reading 19 for 2. Against the left-handed Elgar, Aaron had two slips, a gully, and a forward short leg, who was the only fielder on the leg side apart from mid-on. The third ball of his over was on Elgar's pads. He clipped it away easily for four. Short leg retreated to square leg. Later in his spell, he would trouble Elgar with a couple of nasty short ones, but with Elgar fending rather than hooking, the absence of the short leg fielder seemed glaring.

Second ball of Aaron's second over, to Hashim Amla, was short and wide and put away to the point boundary. Point went back. With South Africa 33 for 2 and India right on top, their fastest bowler was bowling with a fielder sweeping on the off-side boundary. A fielder placed for the bad ball, but it didn't feel like a defensive move. It was almost forced on Virat Kohli by Aaron's waywardness. The last ball of the over was short and wide again, and Amla took two runs to the man at deep point.

But just when he was displaying the worst side of his bowling, Aaron let loose an unplayable delivery. Fast, on a fullish length, angling into off stump and straightening. The pace rooted Amla's feet to his crease, and the ball beat his outside edge and hit the top of off stump. Bang. This was why India had picked Aaron.

A few hours later and just over a thousand kilometers north of Bangalore, Umesh came on to bowl with the second new ball. He had dismissed one of Rajasthan's openers with the first new ball, and now he was bowling with the scoreboard reading 216 for 7.

In three balls, he ended Rajasthan's innings. First, the left-handed Kukna Ajay Singh, caught behind, with the keeper diving in front of first slip. "Next two [Aniket Choudhary and Nathu Singh] were cleaned up, with pace," says Paras Mhambrey, Vidarbha's coach. "Length balls - sharpish, quick ones."

Instead of showing his disappointment at being left out of the Test attack, Mhambrey says Umesh was keen on getting game time.

"He was glad to play a game, rather than just sitting out, and he was happy the BCCI released him, so he could at least get a game. He wouldn't be just sitting out there doing nothing, maybe a little bit of training but no bowling.

"When he knew that he was released, he called me, he said I'm available for the next game, I'm coming in the evening, I'm playing the game tomorrow. There must have been some amount of disappointment, but if you look at it, he took it as an opportunity to just stake a claim again. Kind of a reminder. It's good to know that someone who is in the reserves, unfortunately not able to get a game, he's also in good form. That's a good thing for the selectors as well, and the captain also to be aware of."

There is no doubt the team management took note of Umesh's hat-trick. Still, in the short term, Aaron seems to have done enough in Mohali and in nine overs in Bangalore to retain his place for the Nagpur Test. It will mean Umesh sits out at his home ground.

With India playing most of their Test cricket at home - most likely on turning tracks - over the next year and a half, it seems likely they will have room for only one of Umesh or Aaron at a time. Whoever plays will often get only a handful of overs to bowl, with the spinners doing the bulk of the work.

It is a two-edged sword, though. In India, Umesh and Aaron can bowl in shorter, sharper bursts, mostly with the new ball or when the old one is reversing. Right now, both are at a stage of their development when they perform better when used this way, when their attacking thrust is called upon more than their ability to control a game.

It isn't a surprise, therefore, that both have better records at home than away. At home, Umesh averages 28.22, with an economy rate of 3.66. Overseas, he averages 45.40 and concedes 4.54 runs an over. Aaron averages 40.20 at home, with an economy rate of 3.86, and those figures shoot up to 57.38 and 5.10 abroad.

And while they are yoked together in being labelled "right-arm fast", Umesh and Aaron are very different bowlers. Umesh thrives when he can ally pace to movement in the air - whether it is conventional swing, as on the tour of Sri Lanka, or reverse, as when he trapped Ian Bell and Samit Patel off successive deliveries in Ahmedabad in 2012.

Aaron is a little quicker, his skills a little less subtle but no less effective on his good days. His best moments so far include the bouncer followed by the full, fast inswinger to clean up Moeen Ali at Old Trafford last year, and the pinpoint short ball that caused Brad Haddin to fend to short leg at the Gabba a few months later.

At their worst, both can leak runs by the bushel: among bowlers who have sent down a minimum of 1000 deliveries in Test cricket, Aaron and Umesh are among the worst four in terms of economy rate. At their best, they offer India's pace attack a genuine cutting edge.