Weir, who has been associated with Rovers for 22 years as player and manager, told the Carluke and Lanark Gazette: “It’s the September Weekend so I’m going to be away for the game. I’ll be in the Lake District.
"I’m gutted to be missing it. These are the games you look forward to and want to be involved in.
"It would probably have been my biggest management game to be involved in.
"Kenny Neill (assistant manager) will be taking over again. It’s not ideal but I’ve had this holiday booked for months in advance.
"I’ve never known us to play games on the September Weekend. We always used to get the option of not playing because a lot of people do go away.
"I also have three senior players away, in addition to a long injury list.
"So a lot of our under-20s players will probably be thrown in and get a chance.
"We just need to get on with it and deal with it.
"Hopefully we can get a wee result and hopefully get a team just as big as Auchinleck in the next round.”
Rovers go into the Auchinleck clash on the back of Saturday’s morale boosting 4-2 West of Scotland League Conference B win at Renfrew.
Despite having Steven Frame sent off in the second half, Rovers prevailed thanks to goals by James Frame (2), Dylan Duddy and under-20s star Dominic Small.
Weir said: “On Saturday, everything I asked the guys to give me, they gave me.
"My Saturday was superb for a change. I’m delighted for everybody. The under-20s – also including Liam Sneddon, Callum Neill and Mark O’Reilly - came in and stepped up to the mark.
"They were more than capable and held their own which was very pleasing.”
Heading into the Auchinleck clash, Weir revealed that Rovers’ staff and management are taking inspiration from the exploits of Livingston and Motherwell last weekend in beating Celtic 1-0 and drawing 1-1 at Rangers respectively.
The ’Well fan added: “Of course that inspires us. We are at home so you are always looking to win regardless of who you’re playing.
"It is a cup game, so if you put in the effort, fight and commitment, anything can happen in the 90 minutes.
"We will need to see what guys are available but I’ll not be looking to sit back.
"I’ll be looking to have a go. I maintain, I don’t mind getting beaten as long as we’ve gone and had a go at the opposition.
"You can always say: ‘We’ve tried it, we’ve gone for it’.”