The idea makes zero sense.
At 4,200 seats, Muni is far too small to work as a temp park. There’s not enough space behind the old grandstand to build the extra seats and a new press box that MLB would require. Even the area beyond the outfield is limited, so little seating could be built there. Muni is set up so that the clubhouses are on the same level as the single concourse, requiring the park to be quickly emptied of fans after every game. The lack of parking and public transit at the site would make it a logistical nightmare for daily 20,000-person crowds.
About the only thing Muni has going for it is that it’s a baseball field with some seats around it. That’s not the expensive part. It’s everything else (additional seats, suites, infrastructure) that’s expensive.
Using Muni makes even less sense when you consider that the City of San Jose inked its own five-year extension with the San Jose Giants only two months ago. While the lease is quite cheap at $25,000 per year, naming rights to Muni are involved and the fact is that the City would have to break the lease to accommodate the A’s.
I understand that Lew Wolff will look at a number of sites and facilities to get a feel for what’s possible. A temporary ballpark at San Jose Muni is more than a little far-fetched.
P.S. – Candlestick Park was also reported to be in the discussion, but demolition is expected later this year.