The Sulphurites make the long trip down to the South West to tackle an in-form Gas outfit having won just one of their previous seven matches and coming off the back of a disappointing home defeat to Hartlepool United.
Not for the first time in recent weeks, Town conspired to drop points in a game which they had got themselves in a position to go on and win when they entertained Pools, with a couple of slack moments deep inside their own half again proving costly.
Thus, Harrogate's assistant manager says that his players need to remain switched on for the duration of matches in order that they start coming away with more to show for their efforts.
"We can keep saying that we've been unlucky in games, but if people don't do their jobs properly then you get punished," former Sunderland midfielder Thirlwell told the Harrogate Advertiser.
"It's not acceptable for anyone to be thinking 'somebody else will do that'. We need everybody to be prepared to roll up their sleeves and do what is required of them.
"We seem to have to work very hard for our goals or to get in front in games. You can never say that this group of players aren't hard workers, but we need to be working just as hard at the other end of the pitch to deny the opposition chances to score.
"It's these switch-off moments in games that have been costing us and as a management team, we continue to drill it into the players that they cannot afford to lose concentration and focus.
"What we can't replicate in training is the atmosphere of a game, the noise of the crowd or what's going through someone's mind if they've just misplaced a pass a few moments earlier. But we cannot just keep saying we're new to the level and playing in front of Football League crowds. People have to stand up and do their jobs for the full 90 minutes."
Town travel to Bristol 14th in the League Two standings, while the Gas are 11 points better off in ninth having lost just once in eight matches.
Joey Barton's team's most recent outing saw them beat Crawley 2-1 away from home in midweek.
"I've watched that game and there wasn't much in it really. It was one of them that could have gone either way, but with the run Bristol Rovers are on and the momentum they have, they ended up on the right side of the result," Thirlwell added.
"I don't know how different things are down there compared to the start of the season when they were struggling for a while, but they are certainly playing well at the moment and we know it's going to be a really tough game.
"But it's one of those fixtures at this level that you have got to really be looking forward to. After Bradford, it's up there with one of the biggest crowds we will play in front of this season and we have to embrace that.
"We were disappointed after the Hartlepool result but you have to pick yourselves up, be upbeat and positive and look to the next one.
"Hopefully having a week without a Tuesday night fixture has come at the right time for us and we'll go into Saturday a little bit fresher."
Town's only previous meeting with Rovers saw them lose a scrappy affair 1-0 at Wetherby Road back in October, Nick Anderton netting the only goal of the game on 64 minutes.
Kick-off at the Memorial Stadium on Saturday is at 3pm.