Trainer Andrew Williamson has one lingering doubt about the chances of smart galloper Darci Be Good breaking his middle-distance duck on Saturday.

Formerly trained by Bede Murray at Kembla Grange, Darci Be Good was a fast-finishing third over 1600m at his first run for Williamson at Eagle Farm two weeks ago.

Williamson had him entered for a 2000m race that day before deciding to take a more cautious route.

But on Saturday the horse will tackle middle-distance racing in Brisbane for the first time in the Bell Plumbing Open Handicap (2020m).

"We didn't want to knock him about at his first run up here so we stayed at the 1600m," Williamson said.

"He ran a really nice race and that should have topped him off nicely for 2000m. But I still have that one little niggle about him running a strong 2000m. He has run some good races at the trip but never won.

"Then again, we are talking about Brisbane staying races compared with Sydney and he is older now."

Darci Be Good has had six tries at 2000m for two seconds, including in the 2011 Spring Champion Stakes when he was runner-up to Doctor Doom.

He was also second to Moriarty over the distance in last year's Tattersall's Club Cup at Rosehill.

"It is good form for a race like this but it is old form," Williamson said.

Darci Be Good's last win was in the Hawkesbury Gold Cup in November 2012 but he has been Group placed three times since then.

"The change of scenery seems to have done him the world of good. He seems to be loving the Queensland sunshine," Williamson said.

"And I must add Bede (Murray) has been a great help with advice on how to handle him."

Glen Colless replaces the suspended Damian Browne aboard Darci Be Good at Doomben.

"They are both Group One jockeys so we don't lose anything. Glen is renowned for his ability to judge pace in races," Williamson said.

"There looks to be a stack of early pace in this race and he should be able to get Darci Be Good into a nice position."

Darci Be Good will remain in Brisbane in the short-term but the handicapper could play a role in his future.

"It doesn't take them long to get up in the weights here," Williamson said.

"But we will worry about where he races if he wins a couple here."