I would assume most of the renovations, if they did them, would be coordinated with the seasons. I.e., stuff in the concourse during the season, stuff in the seating area during the off season. It's not like they have to gut the Rose Garden and it will take years to upgrade things. The biggest obstacle/hardest thing to build is the shell, and it's perfectly fine.
But like I had suggested earlier (and that rat bastard Sly tried to take credit for it), they could build up something outside of the arena to create a new covered area, and that way the area that they can renovate doesn't necessarily screw up the concourse or the natural flow of fans.
I.e., They could build a covered area between the Moda and the MC, and enclose some of it which would expand the concourse while they remodel it.
There are plenty of options to make the remodel doable with the team playing or at least during the off season.