It's not just the Jays games that often use TV audio on the radio as a money saving move. It used to happen with the Toronto Maple Leafs, too. According to the article below, they tried it back in 1956, with Foster Hewitt calling the Saturday night action on Hockey Night In Canada and the station he owned, CKFH. 

But unlike Rogers, he quickly realized it wasn't practical and didn't serve listeners. So it ended for good in 1957.

Which brought yet another Hewitt to the fore - his son Bill, who eventually wound up with quite a long track record on the big broadcasts for many years. But he got more exposure because the radio/TV simulcast didn't work.