The Awapuni jockey will replace the suspended Leith Innes aboard Rasa Lila in Saturday's Group I Rydges Wellington Captain Cook Stakes.
"He has ridden quite a few winners for us," Ramsay said.Riddell had three Group placings from five mounts on Guiseppina for the stable and partnered the mare when she was runner-up to Shez Sinsational in the Gr.1 Spring Classic at Hastings.
Rasa Lila has been freshened after finishing fifth in the Livamol Classic on October 1, when she was unsuited by a slow track.
"She kept coming, but she couldn't show her best in the conditions," Ramsay said. "She's got an explosive sprint when she's right.
"We are really pleased with her at the moment. She's a bit stronger now and is a happy horse and enjoying life. She goes well fresh and will be suited by a big track.
"She had a really quiet trial the other day, with Julia riding her, just to give her a day out and she went well."
The Captain Cook will also serve as Rasa Lila's lead-up to the Gr.1 Zabeel Classic at Ellerslie on Boxing Day.
She will be accompanied to Trentham by stablemate Seraphim, who will contest the special conditions maiden 1600m.
By Rip Van Winkle from the Caulfield and Melbourne Cups winner Ethereal, she easily won a maiden 1400m at Avondale at her last start.
"We have had to wait for her to strengthen up, but it was a good run last start," Ramsay said. "It was hard to make up ground that day and she settled last and was too good for them." – NZ Racing Desk.
