Butera generally has been good at avoiding using relievers on consecutive days. Occasionally, some bottom end guys will wear one for the team after a short appearance the day before, but I spotted only one abusive day, 4/8 vs the Cardinals. That game, he left Henry in for 43 pitches trying to go 2 innings after he had thrown 16 the game before, then went to Poulin on consecutive days to try to get out of the mess Henry couldn't finish.
It was a 4-1 Cards game when Henry came in. Low lev. Lord and Perez had already pitched earlier after Mikolas was pulled after 3 (and allowing 2 runs). Varland had blown a lead the day before, and Beeter and Schultz had also pitched. With 5 relievers used the day before and 2 others prior to the 8th, perhaps there was going to be a need for some back to backs that day. Henry threw 22 pitches in a clean 8th. Had Butera pulled the plug at that point, it would have just been simply abuse of one of your better relievers, but he brought Henry back for the 9th, when he blew up and. Infamously, Henry's one time was called out as abuse here by Slate, and may have been the start of the latest arm issues. That seems like the worst bullpen management so far this year.
Use so far on consecutive days for main relievers:
Varland - 13 games, one time on consecutive days (4/25 & 26 - 18 pitches total)
Lovelady - 6 Games with Nats, 2x on consecutive days (4/17 & 18 - 51 pitches; 4/23&24 - 21 pitches)
Poulin - 16 games, 4x on consecutive days
Perez - 15 games, 2x on consecutive days (4/5&6 - 41 pitches; 4/10&11 - 28 pitches)
Lord - 10 games, 0x consecutive days
Parker - 5 games, 0x consecutive
Schultz - 7 games, 1x consecutive
Granillo - 6 games, 1x consecutive
Henry - 7 games, 1x consecutive (16 pitches then 43)
Beeter - 10 games, 1x consecutive
Waldichuk - 5 games, 0x consecutive
More or less, other than Poulin, Butera generally avoids back to back. Granillo was sent down after the second game of his back to back; that one, he was clearly taking some abuse for the team. After a 5 pitch appearance on 4/16, Schultz did 3 innings of middle relief when Littell blew up for his 1 back to back.
In two of Poulin's consecutive appearances, he threw 20 and 24 pitches total; once he threw 42, 15 after 27, but that second appearance was to get one out at the end of the Henry game noted above on 4/8. The final back to back was 4/19 & 20, where he came in behind Irvin and blew a lead in the 6th; on that occasion, he threw 11 pitches after 16 the day before.