Borthwick: RFU in talks about reviewing overseas selection policy
The RFU's policy restricts Borthwick from selecting players based outside England unless under exceptional circumstances, like in the case of Jack Willis who moved to France after leaving Wasps when they went into administration.
Luke Cowan-Dickie, Sam Simmonds, Joe Marchant and David Ribbans are set to join French clubs after this year's World Cup, while Manu Tuilagi and Billy Vunipola have also been linked with moves to Japan.
With overseas clubs able to offer more lucrative contracts than the English Premiership teams, there are fears England will lose many players.
"What we are faced with here are some extreme circumstances," Borthwick said.
"There are discussions ongoing about what this means and what the implications are going forward. It's about the players' livelihoods and careers as well."
Borthwick said that his current focus on England's Six Nations campaign, with the team due to play in Wales on Saturday after losing their opening match to Scotland and beating Italy in the second game.
"From my point of view I want to make sure we are able to select the greatest number of players possible. And the best players possible," Borthwick added.
"Those discussions are only at their starting point and clearly my focus is on the Six Nations. But do I want to make sure we have an England team where we have the best players available to us? Yes."
