Their pitching is decimated. Very little of it is playoff quality at this point.

Yamamoto is still trying to find his way back after an extended time out with an injury.
Flaherty has been good for the Dodgers this year, really good, but his last few outings haven't been as good. He may be wearing down after a long season.
If not for all the injuries to pitchers this year, Knack would still be in the minors. He's done well, but he's not yet a frontline, playoffs-ready pitcher.
Buehler is kind of a wildcard. He's been pretty bad since coming back from injury, but his last couple of starts were decent. We'll see.

So many pitchers (both starters and relievers) out with injuries, that it's been clear for awhile that it's unrealistic to expect a deep run by the Dodgers this year.
Plus, for the last few years it seems the Padres have been the Dodgers kryptonite. Their lineup and pitching are both much improved.

Bottom line, I'll be happily surprised if the Dodgers win the series. They only way they can, in my opinion, if they consistently score a lot of runs in every game, because I don't expect stellar pitching from the Dodgers. And the Padres pitching is good enough that I don't see LA consistently putting up big offensive numbers.