That certainly is a strong possibility, but there are likely other reasons.
As much as hot streaks seem contagious, so do slumps. Of course, this can't be all to it, either, but it may contribute to the cluster you-know-what.
It's never a great idea to put a lot of faith in rookie and two year players, but we did keep 4 OF'ers as insurance against a drop by Anthony, and the 2B position was apparently not handed to Mayer before ST'ing began. (The infield depth was not nearlt at the level as the OF, so it did look obvious that not many other options were too viable at 2B: IKF, KC, Monasterio, Seigler, Cheng, Sogard, Capra... Lots of name but not much hope.) The Catcher position was handed to Narvaez and running Wong back as the #2 seemed skeptical. The front office added a lot of minor league depth at the C position, even down to the lower levels, but Delay or Thaiss are not anyone you get excited about.
To me, the killers go beyond big let-downs by vets like Story & Duran, but let's not minimize how much both have dragged this team down. Those two were the senior batters in the organization and they have flopped mightily. It's hard to be a leader when you suck, and if you were a leader by example, it's even worse.
The younger players always have to be viewed with speculation, but it does seem unexpected that nearly all have failed to show any growth- Abreu & Rafaela as the only exceptions. (Their growth has been minimal and not earth-shattering.)
Anthony, Mayer, Durbin and Narvaez could have expected second year struggles, but all four at once hurt us badly.
Contreras has not declined as some thought he might due to his age, but he can't do it all.
The in system options might have some nice numbers in AAA and AA, but most offer little hope. What Gasper has done in his short time should not be something we can expect to last or be duplicated by these guys being called up:
AAA
.957 Capra (infield)
.871 Sogard (1B & infield)
.853 Ward (OF)
.822 Seigler (UT)
.792 Delay (C)
.725 Campbell (DH?)
.710 Thaiss (C)
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AA
1.257 Brannon in just 51 ABs (1B/DH)
1.072 Arias (SS)
.880 Ferguson (infield)
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A+ (No way we jumps these guys to MLB)
.963 YRod (OF)
.930 Godbout (2B)
.885 Cespedes (DH)
.880 Gonzales (OF)
Of course making some splashy trade for someone like Paredes or even Yordan had gotten some talk, would that be enough? Even if we got both? And what do we give up to get them?
It's gonna start with Tolle or Early & Arias or Mayer and maybe 3 of these 4.