The trio are currently training with Owls’ development squad, having been frozen out at Hillsborough.
Boss Carlos Carvalhal told The Star: “They belong to Sheffield Wednesday but are not included in the first-team squad. They are available for transfer and free to go.”
Defenders Lachman and Dielna have never played under Carvalhal and were farmed out on loan to SC Cambuur Leeuwarden and Slovan Bratislava respectively last season.
Romanian striker Bus made three substitute appearances during the 2015/16 campaign, with his last outing coming at Rotherham United in October. He joined Italian side Salernitana on a temporary basis in February.
When quizzed on any other potential departures this summer, Carvalhal said: “We analyse the players very carefully. They are doing the maximum in training.
“We want to give everybody the opportunity to play. We are looking at their behaviour in the games and training and after that we will make decisions.
“We will be with the (squad) number that we want. We don’t want too many players or too few.”