Yeah, but that may be over-simplifying things.
Here's the Cook Report analysis I posted a while back that sets out mile markers for Sanders to get 50% of the delegates (set aside super-delegates for now; if he gets >50% of delegates things could change). Sanders is well behind pace even after doing better than many had expected over the last week or so. In fact I think Michigan was the only state where Sanders out-performed those delegate targets.
The targets have him winning by 23 at this juncture instead of trailing by about 200, so if he's gonna hit 50% he needs to find about 225 delegates above and beyond those numbers. I'm just not sure you can find them in the states that are left; the Cook Report numbers already give him basically a 50/50 split in Ohio and a dominant margin in the NW. Maybe California? I have no idea whatsoever what's going on out there. Maybe that plus smaller pickups in Indiana (which seems like it would be Sanders-friendly) and maybe big wins in Wisconsin and Pennsylvania, well beyond the numbers that already assume he wins there.