Not much. The roster doesn't need a complete overhaul. I think they should basically re-roll in 2018 with a similar core.
They've been horribly unlucky this year. That might be a reason to give up on 2017 early but it shouldn't be a reason to give up on 2018 as well.
At the deadline this year a few players like Liriano, Estrada, Bautista, Smith, Grilli could have some value and could return pieces that will help next year.
One interesting way to re-tool for 2018 would be to stretch Biagini out in the 2nd half.
The 2018 team would have much better depth when you consider the trajectory of some of the prospects in the system. It would be the same team as this year, but with a shot of youth.
- Stretch out Biagini
- Sign back Estrada or get some other FA.
- SRF, Greene, and Harris are all in AA this year and for 2018 will be viable depth options (AAA won't be a wasteland of forgotten veterans). Big difference from this year. Greene and SRF are pen options too given their stuff.
- Alford, Pompey, Tellez, Gurriel could supplement the MLB roster. Depth players like McGuire, Ramirez, DSJ, Urena will be more seasoned.
- Bullpen: Who really cares, but it's notable that Tim Mayza could/should be an impact RP.
If it doesn't work, just trade Donaldson next deadline