Trengove and Clark played three and a half quarters for affiliate side Casey Scorpions in a practice match at Cranbourne on Saturday, but the club is yet to make a call on their availability to take on Port Adelaide.
Both will face fitness tests early in the week, and then it will be a call for match committee ahead of next Sunday's game.
"We've been very progressive over the whole pre-season, and now just because it's round one we're not going to rush them because of that," Melbourne football manager Josh Mahoney said.
"It'd be hard to put a percentage (on it), both of them would be a chance."
"If all the information's there and says they're right to go, then we'll definitely be playing them."
For Clark it was a return to football after nine months out with a serious foot injury.
He kicked one goal late in the first term and spent no time in the ruck.
"He was nervous before today's game, he hasn't played for nine months. He just wanted to remind me of that, that he looked a bit rusty out there because he hadn't played for that long," Mahoney said.
"We have to remember even when he starts playing again for Melbourne, it's going to take him some time, because he's missed a lot of footy."
Trengove, also returning from a foot injury, appeared cautious at times, although laid some strong tackles and took a couple of impressive marks.
Viney's likely debut is set to excite Demons fans, after a year preparing at VFL level.
"We were really keen for him to get one more game, and he performed really well, so we'd expecting him to be very close to be playing," Mahoney said.
Former Magpie Chris Dawes didn't play, but is expected to be in contention for AFL selection.
"He's trained really well this week, he'll train fully next week, and again we'll consider him if he's ready to go," Mahoney said.
Any hope young Melbourne draftee Dean Kent may have had for an early season debut may have been dashed.
Kent, from Western Australia, will come under scrutiny for a hit late in the first quarter.
Mahoney expects the Demons third pick in last year's draft will play AFL at some stage this season.
Matt Thompson is a reporter for AFL Media. Follow him on Twitter @MattThompsonAFL
