Clark suffered an ankle injury during the second quarter of the 31-point loss and did not return after half-time where he was replaced by substitute Patrick Karnezis.
Small forward Banfield limped from the field with a hamstring injury in the last quarter and also did not return.
While Voss said both would not be scanned until Monday, he was not holding much hope.
He said he thought Banfield had a "grade two" hamstring, but was much clearer on Clark.
"Categorically he'll be out next week," Voss said.
The pair joins a long list for the Lions this season, with vice-captains Daniel Merrett (back) and Jed Adcock (finger) currently the biggest names on the sideline.
Captain Jonathan Brown (facial fractures), Josh Drummond (knee and quad) and midfielder Tom Rockliff (calf) have also missed matches.
"That's just the lie of the land," Voss said.
"We've had that run, it's not great to have, but at the same time it presents opportunities for others. I'm not going to look at it through rose coloured glasses though, we want our best team out there and we haven't been able to get that for most of the year."
On Saturday night the Lions had whittled away a Tigers lead to just four points early in the final quarter before the visitors drew away to win comfortably.
Voss said the Lions did not make the most of their opportunities.
"We had our ascendency at different parts of the game," he said.
"You do have momentum in games and how you maximise that is important. In the first quarter I thought we were very, very good but they kicked a couple of late goals and they all matter in the end.
"We talked about excellence and that attention to detail, the little things. Sometimes the game looks more complex in nature because you've got 18 players running around, and there's forward presses and stoppages and these terminologies, but sometimes it can just come down to basics like manning the mark.
"That's probably been a common theme throughout the year, not just tonight, but we'll continue to work to find that absolute excellence."
Voss said Jack Redden, Matthew Leuenberger and Tom Rockliff were his team's best players.
