Donal Lenihan believes that Tadhg Furlong is so key for Ireland that the outcome of Saturday's RBS 6 Nations clash with Wales rests on the tighthead prop's fitness.
Furlong is racing against time to get himself fit for he Aviva Stadium game having suffered a hamstring injury early on in the big win over Italy at the start of February.
He only took a limited part in squad training on Tuesday and Ireland head coach Joe Schmidt usually operates a policy where only players who train fully on Tuesday get to play at the weekend.
Lenihan feels that Schmidt may make an expection for Furlong because he is so vital for the gameplan.
"There has been so much talk about England and an almost dismissal of Wales, which is a huge mistake," he said, speaking to RTÉ Game On.
"They're a very good team to achieve what they have in the first two games short of nine British and Irish Lions and they'll have no inhibitions about playing against Ireland.
"I think if Furlong is there and they impose themselves up front as they are capable of, then I'd go for Ireland for a home win. But we have to tick all the boxes and Furlong is such a key player.
"Tadhg Furlong's fitness is going to have a huge say in this game. If he's not fit, that Welsh scrum, an all-Scarlets front-row, have been really impressive in the Championship so far."
Lenihan cautions against taking a chance on Furlong, pointing out that if he breaks down early in the game it uses up a valuable replacement and risks ruling the man rated the top tighthead in the Northern Hemisphere out for the last two games of the Six Nations.
Leinster's Andrew Porter came on for the Wexford man in the win over Italy and acquitted himself well and would appear to be the obvious replacement.
But with only four caps under Porter's belt, Lenihan reckons that the more experienced John Ryan from Munster, 12-times capped, would be a better bet.
"Knowing Gatland, if a young player like Porter is starting his first Six Nations game, you can be sure Gatland is going to go after him. Bringing a player on after half-an-hour or 50 minutes isn't just the same," he warned.
"The fact that John Ryan has played so many times against the Scarlets, I'd be inclined to start him ahead of Porter. It's going to be a big call. It'll be a huge loss if Tadhg Furlong doesn't start."
Follow Ireland v Wales on Saturday (KO 2.15pm) via the live blog on RTÉ.ie/Sport and the News Now App, or listen live on RTÉ Radio 1, with commentary from Michael Corcoran and Donal Lenihan.
