Not sure Doolittle will agree to a "phony" DL stint when he has a lucrative vesting games-finished option. He could easily file a grievance with the MLBPA saying the team is just trying to get out of it.
And if he weren't rocking an ERA over 5 in the second half, he might have a case.
Oh and he's admitted he's tired:
https://mlb.nbcsports.com/2019/08/13/sean-doolittle-concerned-about-workload/The lefty said, “I haven’t really amassed this kind of bulk in several years. There’s nights like last night where you feel a little bit out of wack, a little bit sluggish. It catches up to you after a while.”
That plus altering his mechanics has really been a problem. Ever since Maddon protested the game in May, Doolittle has struggled:
Pre-Joe Maddon: 1.71 ERA, 2.31 FIP, 10.71 K/9, 2.57 BB/9, 0.43 HR/9
Post-Maddon: 5.16 ERA, 4.43 FIP, 10.01K/9, 1.82 BB/9, 1.82 HR/9
And it seems like every time he does an interview, he talks about altering his mechanics in some way. I think he knows that Maddon was right and that he was touching the ground prior to his pitch. He is trying to fix it during the season, but because of his workload, he can't really dedicate any time to a bullpen session. A trip to the IL would allow that.