Johnson, who holds the Commonwealth version, was all set for a two-belt battle on the Anthony Joshua v Carlos Takam undercard in Cardiff until disaster struck.
“I’m sorry to say I’m out of the fight on Saturday due to health / injury reasons,” outlined Johnson.
“There’s no-one more gutted than me I’m truly devastated and I’m truly sorry to everyone that was going to support me.
“I’ve put a lot of hard work into training and sacrificed being away a lot from my family and my two boys.
“I’m missing out on a childhood dream and adding another achievement to mine and my dad’s collection. And also losing a few quid on top of it all as we don’t get paid when we don’t fight.
“I’m hoping everything will all be OK and I’ll be fighting fit again very soon and the fight can be rescheduled for a later date.”
Craig Richards, who fought just last weekend when defeating Norbert Szekeres, has now stepped in for an unexpected shot at the Lonsdale Belt.
Buglioni didn’t seem too disappointed about the switch and vowed to keep a tight grip on his strap whoever opposed him this weekend.
“Credit to Richards stepping up to the plate. The result, however, stays the same,” said Buglioni.