India skipper Virat Kohli will be allowed to bat at No. 4 in the ongoing Ranchi Test against Australia, as the article 2.5 of MCC states a player can only come out to bat after spending an equivalent amount of time on the bench, for which he was absent from the field.
The same thing happened in the D/N Test between South Africa and Australia (last year) at Adelaide when Faf Du Plessis declared the team’s innings on 259/9. The Proteas skipper knew David Warner, who wasn’t on the field due to a minor injury issue, wouldn’t be allowed to open the innings as he was already off the field.
But in Kohli’s case this rule won’t apply, as he landed awkwardly on his shoulder and has suffered an external injury and there is no mention of the same in the MCC laws.
Hence, Kohli can come out to bat at No. 4 position, regardless of whether the first two wickets of India fall in first five minutes or five hours.
Here is the Law 2.5 of MCC:
If a fielder fails to take the field with his side at the start of the match or at any later time, or leaves the field during a session of play,
(a) the umpire shall be informed of the reason for his absence.
(b) he shall not thereafter come on to the field of play during a session of play without the consent of the umpire. See 6 below. The umpire shall give such consent as soon as is practicable.
(c) if he is absent for 15 minutes of playing time or longer, he shall not be permitted to bowl thereafter, subject to (i), (ii) or (iii) below, until he has been on the field for at least the length of playing time for which he was absent.
(i) Absence or penalty for time absent shall not be carried over into a new day’s play.
(ii) If, in the case of a follow-on or forfeiture, side fields for two consecutive innings, this restriction shall, subject to (i) above, continue as necessary into the second innings, but shall not otherwise be carried over into a new innings.
(iii) The time lost for an unscheduled break in play shall be counted as time on the field of play for any fielder who comes on to the field at the resumption of play after the break. See Law 15.1 (An interval).
For a detailed explanation see here.