They have depth in the pen in terms of high leverage relievers. Santos/Janssen could be replaced by one of Santos/Janssen, Delabar, Wagner plus John Stilson pitched well in ST and is viewed as a high leverage reliever in the near future. The trade off would've been a better overall team. Let's say they had signed a proven starter and a 2B with the money freed up, that would've made the team better. They kept the strong pen and they've blown 3 leads of 3 or more runs already.
AA said all off season they were looking to add 1, 2 or even 3 starters, he just didn't get it done. He kept waiting for prices to fall until it was too late, it's on him first and foremost, he got too cute.