Lopez has played a fair bit of SS in the MiLB, definitely a utility guy, but played each of 2B/SS/CF a fair bit. Barger has played more SS than any other position. Obviously Biggio and Merrifield only play SS if half the team is in traction, but between those 4 guys Espinal isn't CRITICAL to keep around.
They all (including Espinal) project to be about league average in wRC+ (give or take 10%) with Barger being the highest at 113 (Merrifield at 98 is the lowest, which surprised me...).
We're a bit spoiled for choice w/r/t utility guys at the moment, so it wouldn't shock me to see any of those 5 moved (I guess it'd be pretty shocking to see Barger move at this point in his career arc...)