To add to Radiodizzy a bit...WVEI-AM is also, AFAIK, a 100% repeater of WEEI-AM. In a sense, it helps to think of them as one station. This is especially true after sunset, since WVEI is on a bad channel and has a fairly weak night signal...it doesn't reach very far at all, certainly not in the Framingham/Metrowest gap created by WEEI-AM's own nighttime pattern having a hard null to the west.
There are FCC benefits to doing a 100% simulcast on WVEI-AM; things like the main studio rules, public file, and EAS, can all be more easily waived if WVEI originates no programming of its own. Given that, and what a small impact WVEI-AM has on WCRN during the games (everyone's listening to WCRN), it makes more sense just to leave WVEI-AM as-is, than to try and come up with different programming on WVEI during games.
BTW, I was driving through the Berkshires last week and tuned to WVEI-FM and heard a Yankees game. That was a bit of a shock since I kinda thought the Sox would be on a WEEI-branded signal, ya know? I couldn't remember if anyone had a local affiliation so I left it on WTIC and dealt with the skywave fading in and out as I travelled west on I-90. On a similar note, I was getting the Sox on WRKO as far out as Syracuse, NY (weak, but listenable) right before sunset, and suddenly it disappeared as they switched patterns. D'oh!