They'll need to find two more starters, but I'm a strong believer in Jamie Arnold, Gage Jump, and Wei-En Lin. All three of those guys look like top of the rotation big leaguers. The big righty from Cuba, Luis Morales, would have been a solid bet for #4 based on what he did last season until his control completely abandoned him in his first two appearances this year. Hopefully he just has some (injury related?) mechanical issue to sort out and he'll be back to throwing strikes soon but so far he's struggled with his command in his AAA appearances too.
The difference is this time Fisher needs to spend money to keep getting his portion of revenue sharing and there is an alleged move to Vegas that he needs to be fielding a competitive roster for. The A’s also have signed more guys to long term deals over the last two years than they did in the last decade combined.