Complacent, the Darley stayer rated in early betting markets as one of Australia's best chances for spring Cups success, is unlikely to return to racing until 2015.

The Spring Champion Stakes winner has been sidelined since going amiss with a tendon injury in the early stages of an autumn campaign.

And plans for Complacent to play some part in the spring have been dashed after an updated assessment of the injury.

"He's on a long, extended rehabilitation program from that (injury) and unfortunately he's going to miss the spring," Darley racing manager Jason Walsh told racingvictoria.net.au.

"But hopefully we can have him back for the autumn and then hopefully 2015 might be his year (for the Cups)."

Ex-Darley trainer Peter Snowden had high hopes for Complacent as a genuine Cups contender after he ran second to Polanski in the Victoria Derby.

In Complacent's autumn absence, it was left to Gallatin and Tupac Amaru to carry the bulk of Darley's representation in staying races for three-year-olds.

Gallatin won the Tulloch Stakes and Tupac Amaru finished second to Criterion in the ATC Australian Derby.

But Walsh gave a realistic insight into their spring prospects when he said they were second-tier stayers who could be aimed at races like the Zipping Classic and the Sandown Cup at the end of the Melbourne carnival.