Like, not normal due to what we know about the human body? Or not normal because most teams don't typically use guys they way they use Ashby, because if a team has a guy like Ashby, he's almost never pitching in middle relief?
It's unconventional, yes. But aside from baseball's long-established pitching roles, codified through conventional wisdom, player contracts based on stat-accumulation, video game player designations (CP, SU, RP, SP), and with an assumption that every pitcher experiences the same stress/recovery on their arm every time they throw, why do we assume that the Brewers are babying Miz, and overworking Ashby?
Miz said he had one more inning after the 5th, so that's what Murph gave him. Ashby likes the ball all the time, and the pitching coaches and training staff (perhaps) recognize this and give Murph the go-ahead to use him.
If we can all agree that there is the "right" amount of high-stress pitches over the course of a game, a series, a week, a month, a season, for a starter, or for a closer, why can we not agree that the "right" number of high-stress pitches for a middle reliever may be somewhere in-between?
Last season, Miz threw 129 IP in 28 appearances (27 starts) between AAA and MLB. Uribe threw 75 IP in 75 appearances (19 back-to-back outings), and Ashby threw 66 IP in 43 appearances (3 back-to-back outings).
Ashby is on pace for about 110 IP in about 80 appearances, and has had 3 back-to-back outings. So long as the Brewers keep giving him more days off between appearances as they would a leverage arm, isn't this simply a "Goldilocks" zone of arm usage between a typical starter's workload, and a closer's role?