Talented sprinter Spieth will be aimed at the City Tattersalls Club Lightning at Randwick.
Spieth returned to trainer Bryce Heys' Warwick Farm stables on Monday as a four-year-old with four wins from seven starts.
"He looks great," Heys said.
While a decision on his first-up run is about four weeks away, Heys is looking at the $150,000 Listed City Tattersalls Club Lightning (1100m) at Randwick on October 15.
"That would be a logical step in terms of a Listed race and if he could win then we'll go up another cog," Heys said.
"He will probably trial mid-September and we'll probably just go from there."
Spieth won down the Flemington straight in June to record his third consecutive victory.
Another Heys-trained former stakes competitor Boston Light will be given one more chance as an entire when he runs second-up in a maiden at Hawkesbury on Thursday.
Boston Light had an extended lay off after being galloped on in the Group Two Danehill Stakes at Flemington in September 2015.
"He's showed us that there's plenty of potential but he's caused us a lot of frustration," Heys said.