Newcastle head coach Steve McClaren then defended the club's decision not to recruit defenders in January as he faces a fresh injury crisis during a relegation fight.
The Magpies beat West Brom on Saturday to lift themselves ot of the Barclays Premier League's bottom three.
He said: "We could never have foreseen that (injuries). We had four fit ones (central defenders) all training before the window closed, so no, there's no criticism there.
"We would never envisage that in one game, we would lose three defenders, two centre-halves especially.
"The sending-off right in the last minute was really frustrating because Jamaal was playing well and we'll need Jamaal for the next few games."
Mbemba is the main concern with appointments to see specialists in both London and Belgium about his ankle problem having been arranged, and while McClaren is keeping his fingers crossed, there is a fear that the player's absence could be lengthy.
The former England boss said: "We are still waiting. He's had one scan and I think he is going for a second opinion down in London and also in Belgium, so by the middle of next week, we will really know the diagnosis and how long he will be out."
McClaren, who will miss Lascelles through suspension for just one game, is more hopeful over Dummett after he aggravated an existing hamstring problem, but midfielder Jack Colback, a potential emergency left-back, will not be involved next weekend, leaving his boss with a major headache.