It's really just what Russini mentioned, but couple that with reports that Loomis is willing to give Moore a grace period, seems to suggest that Carr isn't likely in Moore's long term plans. If for no other reason, he's 34 and only has 2 more years on his contract.
Of course, that doesn't mean Carr won't be here this year and it doesn't mean Moore can't change his mind or keep Carr until he does find the solution. Moore has not said anything publicly and I suspect he won't say anything other than I am evaluating the QB position and/or what he said about Carr previously which is something like he has done a lot of good things in the NFL.
As far as Russini's credibility. I tend to think she is credible and a lot of the noise probably has to do with general hostility to the media more than anything else but I, like you, don't really follow her closely.