I thought it was a deeply flawed plan to think Kike and Arroyo could man the middle IF effectively for at least 4 months (and an even worse plan to think Mondesi was the plan B).
I'd disagree.
The setup:
The Sox had Meyer coming up at some point, and were locked into Story for 5 more years (at SS or 2B). So they didn't sign a big-name SS to a long contract. Instead, they signed Duval in late Jan. to allow Hernandez to go to SS. They also traded Taylor for Mondesi, who was expected back early in the year.
For second base, the Sox had Arroyo who during his age 26 and 27 years was a league average bat and played decent 2B. For ML depth they had Chang, who was an excellent defensive MI who could occasionally slug a HR. They had Valdez, Hamilton, and Goodrum at AAA.
So at this point, I wouldn't say "deeply flawed." They're covered at SS, and the Arroyo injury-factor is mitigated by Chang, a bat-first 2B at AAA, a potential speedster SS at AAA, and a break-glass replacement player at AAA. Maybe you want more depth, but Mondesi was taking BP and grounders on April 10, and was the 60-day IL, making an early May possible.
How it played out:
- Hernandez could neither field nor hit, and was given half the season to show it before being moved to backup status.
- Arroyo started, missed most of May, returned, and then was finally injured/demoted in August. He turned in his worst offensive season in his career.
So really after the first month, the Sox needed to fill 2 MI positions, not one (2B). But wait - Chang was also injured in April, so they lost their defensive first SS/2B player, leaving them the AAA group. Mondesi was still expected back, as was Story.
When Chang went down, they used Valdez at 2B for a bit, who hit decently for the most part. Then they traded for Pablo Reyes in mid-May, still with an eye toward Mondesi and Story returning, and Hernandez (as Cora constantly assured us he would) turning in either a decent defensive or offensive season. But in fact he didn't so the Sox had to cover 2 middle infield positions.
Later they traded for Urias.
Overall, I don't think the plan was "deeply flawed" from a decision-making viewpoint. I think it was deeply flawed from a results viewpoint, and I think the reason it failed was shitty information flowing uphill:
1) Hernandez was seen as a reasonable SS, both offensively and defensively. Cora there. Plugging away till Mid June. And beyond, some.
2) Mondesi was seen as a reasonable bet to recover. Whoever made those assessments at various points didn't do a good job. Or maybe Mondesi drew the worst hand possible in terms of recovery.
3) Valdez/Hamilton/Goodrum were seen as reasonable depth. Mixed bag there, and the prospects were still developing, so who knows. (I don't know about you, but I around April 15, if I'm Bloom, I spend $200K for a personal IF coach for Valdez and start him at 2B every single game.)
OTOH:
1) Story returned on schedule. He did not hit, which was sort of forseeable, perhaps, but also not. I call it a push.
2) Arroyo was seen as a decent 2B. He was always an injury risk so the club got depth. I don't think it was forseen he'd suck as badly as he did with the bat. But if it could be that's on the org. evenly - analytics and field staff. Again, I'd call it a push.
3) Chang was as advertised. Bad luck with the broken wrist.
4) Pablo Reyes was an excellent pick-up.
5) Urias seems to be as advertised - a decent 2B with upside in the bat, more so than Reyes.
Overall the pattern seems to be stop-gap fixes based on bad information: Hernandez will hit/field, Arroyo will hit, Mondesi will return, Story will return.
When you add up the failures though, it can also be looked at this way:
1) Hernandez didn't hit (or field.)
2) Arroyo didn't hit.
3) Valdez didn't hit quite enough, and didn't improve his fielding quite enough.
4) Story didn't hit when he returned.
Is that a pattern?