After contesting the final four WSS races of 2018 with Puccetti Kawasaki, Barbera joined the Team Toth Yamaha squad for 2019, and finished fourth in the season-opener at Phillip Island and seventh in the following race at Buriram.
At Assen, he'll pilot a customer Kawasaki ZX-10RR in WSBK for Orelac, whose regular rider Mercado suffered a broken scaphoid in a crash with Alessandro Delbianco last weekend at Aragon. Mercado will have surgery on Wednesday and is targeting a return at Imola.
“It’s unfortunate to get this opportunity due to another colleague’s injury, all my thoughts go out to Tati [Mercado] and I wish him a speedy recovery," said Barbera. "I’m going to give everything for Orelac Racing, they are fully prepared.
"I think that WorldSBK is my category. The team ticks the right boxes and I’m more than ready. Life sometimes gives you an opportunity like this and I want to make the most of it."
Barbera's unexpected call-up comes amid mounting speculation as to precisely what happened to the missing Toth Yamaha R6 bike at Aragon.
Team boss Imre Toth told German publication Speedweek that Barbera had contacted him the night before the race to say he had no wish to take part because he felt the bike was sub-standard, with an old engine and a lack of spare parts.
Barbera himself wrote on his Instagram account: "For my safety and for the safety of the other riders, today [Sunday] I will not be able to start the race, we do not have the means.
"What started as a dream ends as a nightmare. The problems of non-payment and fulfilment of the contract between our main sponsor and the team made this SSP adventure end today, at home, at a race that I was especially excited about."