While Seb Ross was named, they lost Brad Hill for Saturday's match.
Ross and Hill suffered knee injuries in last weekend's narrow win over West Coast and coach Ross Lyon had hoped they would play against the Demons.
Ross is also no certainty yet, with Lyon saying before Thursday morning training that it would take until Friday to confirm his availability.
"The scans are basically clear of structural damage, so it's probably a twist and a bit of trauma, potentially," Lyon said of Hill and Ross.
"We're quite optimistic, but we won't know until the back end of today, how they pull up."
Hill then failed a fitness test at training.
Billings returns after fracturing his leg in the pre-season and then being set back by a hamstring injury, while Jones has had Achilles and quad injuries.
Small forward Jack Higgins also is out with a knee injury, while Josh Battle was ruled out with the concussion protocol.
Zaine Cordy is back for his first AFL game since round seven as Ryan Byrnes was dropped.
The Saints and Demons will head into Saturday night urgently seeking form as they manage the dog days of June and July.
Melbourne are coming off an upset loss to GWS, while St Kilda had a massive scare against the last-placed Eagles before rallying in the second half.
After winning their first four games, St Kilda have not had consecutive wins since this season.
"We've been inconsistent, more probably within games," Lyon said.
"Have we been blown away? Against Adelaide we were ... other than that it's 20 points, 15.
"We've been in most games. But within those games, from a coaching perspective, there have been fluctuations."
Lyon cannot fault St Kilda's effort, but is demanding better team defence and ball use.
"There has been some frustration," he said.
"Our ball use and team defence have been inconsistent, so we're really trying to button down over the next eight weeks - otherwise we are wasting time.
"But we've earned the right. I often just chuckle to myself - if we're fifth on the ladder, we've had our trials and tribulations, I'd hate to think some of the other coaches and clubs, their trials and tribulations have been."
Lyon also noted that when the whips were cracking against West Coast, his players responded.
"In a real sense, when the season was up for grabs, we delivered what we needed to against some really good opposition," he said.
"We take a lot of solace from that, but we need to find that form."
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