My understanding is that the visual aid for 28L is PAPI, not VASI. Unfortunately, it and the ILS have been out of service since early June because they are moving the threshold for 28L northward, farther away from the seawall. With both ILS and PAPI out, you truly are making a "visual approach".
Speaking as an old Army ATC, I cannot imagine why they didn't move the PAPI at the same time they moved the threshold. It doesn't take that long to recalibrate it. ILS does take longer, but an in-place PAPI is a powerful aid to staying on-path and on-slope.