I'm seeking advice regarding the recent reorg and impact I've had in my organization. I am a relatively new project manager on a 12 people team. My direct manager got promoted to the next level and got another team. Now he's my skip manager and run a set of somewhat related projects. He took 3 Senior engineers with him to this new project leaving my team with 0 Sr Engineers, 3 Middle Engineers and 6 Jr Engineers (scope didn't change). Not only we have a big question how we are going to deliver what he previously promised but also we learned that he's transitioning these devs with 2-days notice. The expectation is that these devs won't be dragged in any projects related to my team. It's clear that it will be hard to fulfill such a hole in 2 days.
I am trying to understand what I can do to mitigate the effect of this change of composition. I am concerned the team is not setup for success and we will be accused of not delivering on time. Any advice on how to approach this situation?