That is a very strong assumption to make at this point.
Granted, but the assumption is that this is a recurrence of concussion symptoms. If that's the case, I don't think its that big a leap (with a little general medical knowledge, and none about Backes' case in particular).
You can use Crosby's situation from a couple years ago as the synonymous example.
I think he was up when it looked iffy whether Sobotka and Roy could go. Since they're both back in, (even with no Backes) no need for Andronov. I draw no conclusion about Backes' injury status from this move, unfortunately.
I thought he hurt his shoulder on that hard hit just before he came out after a cut-off 15 second shift (his last) just before the end of regulation. If so, it's already been X-rayed. And, because it has not been announced that he'll be out a long period, I'm guessing that he shouldn't be out more than a few more games.