Hastings, 21, and Horne, 22, will both be making their first starts for the Warriors for the visit of the struggling South Africans, who have lost all six of their opening Guinness Pro14 games, in contrast with their hosts who have won all theirs.
Former Bath player Hastings started games in pre-season and featured off the bench in the opener against Connacht but was injured. He has since been turning out for Currie Chieftans in the BT Premiership. Horne has had some game time as a replacement while also playing for Glasgow Hawks.
“Absolutely,” was Rennie’s response when asked if the former Scotland Under-20 team-mates were ready to step up. “George spent the whole off-season with us and played in the two [pre-season] trials. He has had a couple of cameos of the bench. He has been training full-time with us and he’s a very good half-back.
“Adam Hastings also started the two pre-season games. He played a big chunk of the Connacht game and got injured, which kept him out for some time.”
Glasgow will be shorn of their first rank half-back options during the autumn Tests series, with the likes of Finn Russell, George’s elder brother Peter Horne, Ali Price and Henry Pyrgos all key men for national coach Gregor Townsend, who named 18 Warriors in his squad, plus centre Huw Jones who is set to arrive after playing in tomorrow’s Currie Cup final.
“That played into the thinking,” confirmed the coach. “We had 19 guys named in that Scotland squad and you can add a few injuries to that. We’ve got to go deep with our squad over the next month. This is the chance for Adam and George to lay claim to those positions.”
Asked what Hastings will bring to the side, Rennie replied: “He is young and it is difficult to make comparisons with Finn. He really impressed us in pre-season.
“He has a great work ethic. We asked him to make some changes and he has gone back to club rugby and done that. He has a good skill set. He has the ability to challenge defences and make space for others.
“He’s got a pretty solid kicking game and he is brave. In terms of managing a game he has made improvements in that area and hopefully will see evidence of that tomorrow night.”
Niko Matawalu is also in the starting XV for the first time since his return to the club. A number of Glasgow’s Scotland players are rested for the game against the winless South Africans but full-back Stuart Hogg, who made his first appearance of the season against Leinster in the Champions Cup loss, gets another run-out.
Rob Harley will captain the side from the back row, while former Lions prop Ryan Grant should make his comeback off the bench after signing a short-term deal with his former club.
Glasgow will be looking to get back to winning ways after two bruising defeats in Europe to Exeter and Leinster. Rennie described the past two weeks as “good for us” and when asked to elaborate the Kiwi said: “It is a long process. We won our first six games but we have big strides to make. A lot of it is about our patience and our ability to build pressure. Some good lessons have been learnt and hopefully that will show in the Pro14 over the next few weeks.
“We played a lot of good footie in the past two weeks. We got behind and fought back and we had a fair bit of momentum at 24-18 [against Leinster]. But you have to hand it to Leinster and Exeter because they choked us down and got a result. We’ve got to be better.”
Meanwhile, Adam Ashe will undergo surgery on an ankle injury sustained against Leinster and is expected to be out for ten-12 weeks.