I'm pretty much with you and others. There is no real value on the current roster that will bring a sparkplug, especially in June. As you note, Porcello may be of value to a contender who suffers an arm injury in their rotation . The Sox would give up high side potential and cost control with Benintendi, although he may get dangled or at least asked for by others. Not too likely part of a deal. JBJr is not cheap this year or next, and entering his #30 year of age. I think they would let him go depending on the deal. Hembree plus another player could be of interest to some for 2 AAA, top 100 pitching prospects.
Here's some with literally no independent trade value ( only package deal guys) : Pearce, Lin, Travis, Nunez, Brewer, Thornburg ( when back),Brasier, Johnson, Wright, Poyner, All are currently on the 40 man roster.
A few maybe of independent value: Chavis, Moreland (when back), Marco Hernandez, Holt, Walden (?) . Of these, I think the FO would want all through next Spring except for Moreland.
It is not panic time until at least mid-July but watch the Rangers series closely for any sign of Wild Card life.