That seems the most likely to me, because they can use an N+1 process. In order to do their leading edge stuff Intel has to get leading edge wafer allocations from TSMC, where they will be waiting in line behind established customers Apple, AMD and perhaps Qualcomm (who seems to switch between TSMC and Samsung)Of all the rumors so far, I consider i3's one of the less likely target for outsourcing.
Not to mention the huge PR black eye they'd have from not making their high end stuff in their own fabs.