The 28-year-old Croatian, Town's record ever signing having cost £1.3m when joining from Rijeka in July 2019, has played 19 times for Luton this term, but lost his place to James Shea after a bout of Covid following international duty back in November.
Shea stepped up against Nottingham Forest and has gone on to keep five clean sheets in 10 matches since, another coming this afternoon against Blackburn Rovers, with Sluga not included in the squad.
Ahead of kick-off, it was announced the keeper, who had been heavily linked with a move away from Kenilworth Road to Bulgarian First League leaders Ludogorets side, missed out due to injury.
When asked afterwards to clarify the situation regarding Sluga, who is out of contract in the summer, Jones said: "Let’s not speculate, he’s not injured, so I don’t want to come here and barefaced lie to you.
"Things are in motion and we’ll have a bit more news for you on Monday, then we can explain everything and what’s going on.
"I could barefaced lie and say he’s injured, but he’s not.
“I can’t say that (he won't play for Luton again), there are certain things going on that we felt, today, would be better not to put him in.
“His mind has to be on it, but he’s been fantastic for us.
"A great attitude, we love Simon here, but things are happening and we just had to take him out of the firing line today.
“It’s not an injury, I don’t want to categorically lie to you.
"I like to be honest, but rather than probe it and keep saying the same things, let’s wait until Monday and we’ll have a clearer explanation for you."