Turnbull at Victory to compete for no.1 spot
First-choice goalkeeper Coe will miss the duration of the playoff campaign after undergoing surgery to correct a nerve-related back problem, leaving Kevin Muscat's side short of cover between the posts at a crucial time.
Thomas, 22, has acquitted himself well since replacing Coe in the 3-0 win away to Wellington Phoenix on April 5 and - barring injury or a spectacular loss of form - is likely to keep his place as Victory push to win their first title since 2009.
But there will be an experienced shot-stopper on the bench and ready to step in if needed, former AS Roma and Standard Liege player Turnbull having been plucked from the relative obscurity of the Brisbane Strikers to serve as understudy.
"He's coming in to compete," football operations manager Paul Trimboli said of the one-time Olyroo.
"Lawrence is the incumbent and he's played well the last three matches."
Asked if Turnbull will be available for the final round of the regular season at home to the Central Coast Mariners on Sunday, Trimboli said: "We're working toward that outcome."
Once considered one of the rising stars of Australian football, Turnbull was in Australia's squad for the Sydney Olympics in 2000, alongside Mark Bresciano, Mark Viduka and Jason Culina.
Still only 34, his career never hit the heights of those green and gold greats, but the ex-Bristol City and New Zealand Knights man now has a belated shot at tasting success.
"Michael's come here, he's very positive," Trimboli said.
"He was really looking forward to the experience. He didn't baulk at all when we said we'd like to bring you down, even though it's only for potentially a month. I think he'll be good around the group. He's very experienced. (He) spent time in the old NSL (National Soccer League), the A-League and obviously in Europe.
"He went abroad, playing in Italy and England. He fell out of a love, he said, a little bit with the game."
Having reminded Australian football of his existence during the inaugural FFA Cup last year, perhaps Victory's finals campaign will be Turnbull's chance to fall in love with the game all over again.