As India prepare for the one-off Test against Afghanistan, their first long-form assignment since the tour of South Africa in January, they have a number of questions to ponder over. With Virat Kohli unavailable, there is a middle-order spot up for grabs, Wriddhiman Saha's injury opens the wicketkeeping doors for Dinesh Karthik after eight years, and the resting of Jasprit Bumrah and Bhuvneshwar Kumar could mean a return for Umesh Yadav. ESPNcricinfo examines a number of talking points in the build-up to the Bengaluru Test starting June 14:

The opening riddle

For long, M Vijay has been the first-choice Test opener, with Shikhar Dhawan and KL Rahul playing musical chairs. During India's last Test assignment in South Africa, Rahul managed all of 30 runs in four innings, after replacing Dhawan following the loss in the first Test in Cape Town. But he has enjoyed a phenomenal white-ball season since. He was third on the IPL run-getters' list with 659 runs in 14 innings for Kings XI Punjab. Even if Tests are a completely different format, it could still be hard to leave him out on current form.

The first day of India's training at the M Chinnaswamy Stadium gave little away, with all three openers spending considerable time at the nets. They were also among the first to have extended sessions with batting coach Sanjay Bangar.

In the recent past, the selection headache over the three openers has often been resolved by one of them being injured or unavailable for other reasons. Now, with all three fit and available, what does the team management do? If Rahul is a shoo-in, it could mean leaving out one of Dhawan or Vijay.

Vijay's lack of match time and the Kohli puzzle

Vijay has had little match time since the Tests in South Africa ended in January. He featured in just one IPL game for Chennai Super Kings. If he starts, he will be heading into the Test on the back of just training sessions. But he's been the first-choice opener, capable of gutsing it out against the new ball, grinding the bowlers down and occupying the crease: characteristics India will need in England.

Even though the team for that series hasn't been announced yet, chief selector MSK Prasad has already said Vijay will prepare for the Tests by playing for India A, a clear sign that he's still the frontrunner. Where does this leave Dhawan, who has played enough competitive cricket in the lead-up to the Test? Will India play both?

If they do, the other option, possibly the most likely one too, would be to slot Rahul in at No. 4, in place of Kohli, given Cheteshwar Pujara and Ajinkya Rahane are certainties at Nos. 3 and 5. This could then mean his Karnataka team-mate and comeback man Karun Nair, preferred over Rohit Sharma, may have to bide his time before a Test comeback 17 months after he converted his maiden Test ton into a match-winning triple century.

The surface

The previous Test in Bengaluru was played on a dry turner that produced a series-levelling thriller for India, after Australia had bundled them out in three days in Pune. Spin accounted for 27 of the 40 wickets. Nathan Lyon picked up an eight-for, while R Ashwin and Ravindra Jadeja finished with six-fors in the first and second innings respectively. However, that Test was played at the onset of the summer, towards the end of the 2016-17 season.

Bengaluru has witnessed intermittent rain for the past fortnight, the sunshine not as strong as elsewhere in the country, which means the surface has not really had the chance to bake. This has hampered pitch preparation to an extent. Three days from the Test, there was a green tinge on it, even if the extent of greenness on match day is unlikely to be anywhere near what they could encounter a month from now in England. While this isn't to suggest a green-top will be prepared, it may not be a bad option on two counts:

One: it will not only give India's batsmen a challenge in preparing for five Tests in England, while also setting of Test cricket's latest entrants the difficult task of adapting quickly having played and trained on spin-friendly surfaces in Dehradun until a week ago, against Bangladesh.

Two: this could offset Afghanistan's spin threat, given they have four frontline spinners in their squad. This includes two wristspinners in Rashid Khan and Zahir Khan and the mystery element of Mujeeb Ur Rahman, who is fast gaining a reputation for his ability to accurately deliver sliders and carom balls with the new ball.

The fast-bowlers debate

Umesh kept breathing fire on the Chinnaswamy deck at the IPL. His pace, consistency and rhythm for Royal Challengers Bangalore may have helped his chances of returning to the Test XI after he spent the entire tour of South Africa on the bench. Ishant Sharma has just returned from a rigorous county stint in England, where he was devastating in seaming conditions against Warwickshire. There's Shardul Thakur, who has been on the fringes of the Test team for a while, and Navdeep Saini, replacing the unfit Mohammed Shami.

Now, if the team management plays Hardik Pandya as the allrounder, and prefers Ashwin and Jadeja to bowl in tandem, it could mean four fast bowlers fighting for two slots. Do they go in with Umesh based on his IPL show and someone who has toiled hard overseas to build himself into rhythm and gain match-time after being unsold at the IPL auction? Or do they pick one of the two rookies?

What of Kuldeep Yadav?

The flavour on the opening day of India's training session was wristspin. Kuldeep Yadav aside, two other wristspinners, Yuzvendra Chahal and Shivil Kaushik, were called up to bowl for the three-hour session and they kept going non-stop. Incidentally, Kuldeep debuted in March 2017 under Ajinkya Rahane's captaincy. On the eve of that game, the team management had contemplated playing four bowlers and replacing the injured Kohli with a sixth batsman, only for Rahane and the then head coach Anil Kumble to insist on a fifth bowler. India have reaped the benefits of operating with wristspinners in limited-overs cricket. Will they be tempted to play Kuldeep and test the depth of their spin resources before heading to England? The next two days could provide answers.