Van Poortvliet and Steward, known to Borthwick from his days at Leicester Tigers, were both regular starters last year.
But scrum-half Van Poortvliet suffered a tournament-ending injury before a ball was kicked in the World Cup and Furbank inherited the number 15 jersey from Steward during this year’s Six Nations.
“Jack is a player who suffered a serious injury after playing a lot of games for England before the 2023 World Cup,” Borthwick told BBC Radio 5 Live.
“He worked exceptionally hard to come back from that.
“He had a few problems last season and was probably not 100 per cent, but from what I’ve seen in training over the last few weeks, the speed of the ball that Jack brings to the attacking game is exceptional and he’s right, he’s at his best.”
England have shown signs of progress in their attacking intent and have taken a late lead in each of their last four defeats.
Borthwick’s plan to win both the post and the area with a controlled performance almost paid dividends against the Boks at the World Cup before Handre Pollard’s late penalty denied them a place in back-to-back finals.
The inclusion of Steward, a stabilizing presence in the backfield and under the high ball, suggests England may be planning to kick skyward to stifle the visitors and make plays for territory.
Borthwick added: “Now is the right time to bring Freddie in for this game. He has trained really well so far this season and has played really well for his club. George is available and I am pleased with the job he did last time. But last week felt like a physical game for him.
“South Africa kicks more contested kicks than any other country in the world, which means they have to be very good under high balls and good at chasing high balls.”
Meanwhile, Van Poortvliet is a strong box kicker and will look to steer England into better areas of the field and seize the opportunity for Marcus Smith to throw the ball wide to threaten the gain line.
The home crowd has been clamoring for more attacking rugby in recent weeks and although England have gone some way to achieving this, perhaps their best chance of getting over the line against the world champions is to get back to typing and play a controlled game.
