Johnny Sexton has never had the same "resilience" since his ill-fated stint in France and that's why Ireland choose not to select overseas-based players, according to Joe Schmidt.
Ireland boss Schmidt insisted the Irish Rugby Football Union (IRFU) has "no policy" when it comes to omitting overseas-based stars from Test action.
Schmidt admitted Ireland will aim to ignore players plying their club trade abroad where possible, after Simon Zebo signed a deal to join Racing 92 for next season.
British and Irish Lions fly-half Sexton remains Ireland's only star to continue Test action while based abroad, but Schmidt believes his injury-hit two-year stint at Racing continues to impact his career even now.
Asked to clarify the IRFU stance on overseas-based players, Schmidt replied: "There is no policy, there is only an intention from the IRFU to best protect the provinces and the local game.
"We believe that the best way to do that is to select from within Ireland.
"There's one player (Sexton) who went to Racing and was played for the first 12 games in the season, and I'm not sure he's ever had the same resilience since then.
"I think it's pretty self evident: Johnny (Sexton) hasn't played 12 games in a row since then and that's because you pick up the wear and tear and it's hard then to get that back.
"We're looking to add to the longevity of our players."
Sexton suffered hamstring problems then was stood down from action for three months after successive concussion issues during a frustrating time in France.
Munster wing Zebo will link up with Racing next season, and no sooner had he agreed that deal than he was promptly omitted from Ireland's autumn internationals Test squad.
Head coach Schmidt insists Zebo can still force his way into future Ireland squads despite his impending move, and explained that omitting the 28-year-old now hands him a chance to assess future options.
"Simon signing for Racing is an opportunity for us," said Schmidt.
"Simon's had 35 Test matches, we know a lot about Simon.
"What we have done is try to back ourselves to keep people in the country. He's gone to Racing 92 which means he's in a country of 65 million people and 30 professional rugby teams: it's economies of scale.
"We can't necessarily compete, but we have our own ecosystem here that we tend to be able to hang on to the vast majority of players.
"When Ian Madigan went, Joey Carbery emerged. When Marty Moore went, Tadhg Furlong emerged.
"We've got 19 Test matches before the build-up to the World Cup. This is an opportunity for some of the other players.
"It's not a done deal as far as somebody not being able to play for Ireland from outside the country, but...
"No one (overseas) is ruled out. I spoke to Marty Moore, I've spoken to Tadhg Beirne who is coming back next year, I've spoken to Ian Madigan and a few others."