Nb this login tree is flawed as the references to 14 assume that the team is starting with 15 players.
If a team actually have 14 already (eg a there has been a prior unrelated YC or RC . ) then a subsequent front row injury with no replacement would reduce them to 13...
(cue howls of outrage)
That would be assuming that the team was already down to 14 players because a player other than a FR player had been carded and prior to the FR injury, there were still contested scrums and there were no more FR players available to replace the injured FR player.
The reason for my original post was to confirm what happens when a team, that nominated 23 players and therefore had 2 players for each FR position, loses say both TH props (let's say through injury). Even though the team fully complied with the laws at the start of the game, once the two injuries caused the game to go with uncontested scrums, that team would not be able to replace the second injured TH and would have to then play with 14 players.
This is confirmed by Law Clarification 5 - 2015.
Replacement. A player who replaces an injured team-mate.
Substitute. A player who replaces a team-mate for tactical reasons.
Example 1: 3 is injured and replaced (note definition above) by 18 (the declared TH cover). If 18 gets then gets injured the team goes to 14 players and uncontested scrums. (Law 3.5 h, m and t )
Example 2: 3 is substituted (note definition above) by 18 (the declared TH cover). If 18 gets then gets injured then 3 can return and the game continues with contested scrums (Law 3.5 r and s and 3.13)
Example 3: 3 is injured and replaced by 18 (the declared TH cover). If 18 gets then gets temporarily replaced for Blood (Law 3.10) or HIA (Law 3.11) the team can continue with 15 players but scrums become uncontested until 18 returns. If 18 does not return then the team goes to 14 players and uncontested scrums. (Law 3.5 h, m and t)
Example 4: 3 is substituted by 18 (the declared TH cover). If 18 gets then gets temporarily replaced for (Law 3.10) or HIA (Law 3.11) then 3 can return and the game continues with contested scrums. (Law 3.13)
In order to facilitate this process and apply Law 3.5(g) then teams should declare prior to the match (on the competition team sheet) exactly which front row positions that players are suitably trained and experienced to play in. These players can be nominated to play in more than one front row position.
However, (stupid question time again), if a team has been subject to the man off rule and they are playing with 14 players and uncontested scrums, if a LH prop gets replaced and then his replacement LH also gets injured (this team is having a really bad day), because the game has already gone to uncontested scrums, that second LH prop would be able to be replaced by any bench player and they continue with 14 players. Is this correct?