Simmonds will be 29 years old when he arrives at the Top 14 club and, while Eddie Jones expects him to be available for next autumn’s World Cup, once that is complete he will be ineligible to play for England.
McCall believes the departure overseas of a player in his prime has wider implications for the Premiership.
When asked if Simmonds’ move was a sign of things to come, McCall replied: “The answer is I hope not.
“I say that because Sam is 27, nearing his peak and is now making himself ineligible for England.
“I kind of understand someone who is early 30s doing it after they’ve had their international career and want to experience something different.
“But to start losing the best young talent in the Premiership, someone like Sam, is a worry.”
The dire finances of Premiership clubs have resulted in the salary cap being reduced to £5million, but even that has not stopped Worcester entering administration, while Wasps could share the same fate in the coming weeks.
And, while necessary, the cuts to the wages on offer to players has made it increasingly difficult for English clubs to compete with sides in France and Japan and the fear is that other members of Jones’ squad will follow Simmonds overseas.
McCall admits that, with a World Cup less than a year away and the salary cap reduction limiting the money available, keeping a squad together has never been so hard for a director of rugby.
“It’s hugely complicated and it’s one of the more difficult puzzles you can do,” McCall said.
“We had some plus-one contracts (contracts which carry an option for a player to stay for one more year) the players had signed a while back. In the past, you wouldn’t start to have conversations about what is going to happen this year and the year after until October or November.
“Those conversations began on day one of pre-season because you need an understanding of where people want to be in a year’s time. Every decision has an effect on someone else.
“There will have to be difficult decisions made and we need to be skilful about how we do that.”
McCall revealed that Maro Itoje will miss Saturday’s repeat of last season’s Premiership final against Leicester as he continues to nurse a shoulder problem.
Itoje sustained the injury in the latter stages of Saracens’ victory over Harlequins on September 17, but he is expected to return in the next fortnight.
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