Jack Dempsey also has a chance to be involved, but the game is likely to come too soon for Huw Jones.
Franco Smith's side began the new campaign with a narrow defeat by Ulster in Belfast on Saturday but are back at Scotstoun this week to face Benetton for their first competitive home match since being crowned URC champions.
Cummings is progressing well from a foot injury while Horne is close to full fitness following a slightly later return to pre-season training. Dempsey also has a chance of facing Benetton, according to assistant coach Peter Murchie.
"Scott and George would be in the mix," said Murchie. "In terms of guys who are injured, Huw wouldn't be this week but Demmo [Dempsey] could be in the mix. We just need to make sure he's right. We don't want him to be carrying stuff going into it.
"Scott trained fully last week. He did a good bit of training on Thursday and Friday when obviously guys are tapering off for the game. The main group's done some good training. He's ready to go.
"Huw's still a week or so away depending on how it goes. Not him this weekend. We haven't picked up a huge amount from the Ulster game."