A sharp piece of trackwork from enigmatic mare Roll The Bones has convinced John Thompson to run her at Randwick on Saturday.

Roll The Bones will take her place in the Instagram @ATC_Races Handicap (1200m) rather than an easier race at Gosford a day earlier.

"We had her in Friday and Saturday and we were going to decide (based) on her work on Tuesday," Thompson said.

"Her work was very strong so we went for Saturday."

Group Three-placed early in her career, Roll The Bones has struggled to recapture that kind of form as an older horse.

She needed the run first-up when she finished midfield behind Commanding Wit, one of her rivals on Saturday, then failed to handle a heavy Gosford track last start.

However, some of her best results have come at her third run from a spell including a second at Randwick on New Year's Day.

Stablemate Transonic will also line up at Randwick in the McGrath Estate Agents Handicap (1600m), three weeks after winning an 1800-metre open handicap.

"It was a strong race last start and I was a bit worried about that but she won and she won well. She had to do a bit of work early," Thompson said.

"We were going to go to 2000 (metres) but it's just a little bit far so we freshened her and came back to the mile with three weeks between runs."

Transonic is the more fancied of Thompson's Randwick pair at $4.20 in a race that will also mark the Australian debut of imported mare Sabor A Triunfo, a Group One winner over 2000m in Chile who is now in the care of Peter and Paul Snowden.