When you're comparing Bolden and Gillislie as a big back, you know you haven't solved anything.
I was responding to a post that contended that Bolden was roughly the equivalent of Gillislee.
I contend that Bolden is a core special-teamer (first and foremost) and a dire-emergency reserve RB (as Slater is for WR). As a core special-teamer, Bolden (like Slater) will be active every week that he's healthy , regardless of his "prowess" (or lack thereof) at RB.
I contend, also, that Gillislee was (in 2017) the #4/bench-reserve RB, and that one of the four "real" RBs will be inactive every week, regardless how good (or not) they all are.
As it stands, the RBBC consists of White, Burkhead and Gillislee. All of them are NFL-experienced and more than sufficiently competent to make solid contributions to the RBBC unit, each in their own way. The 2018 cap hits of White and Gillislee are very low compared to the 2018 cap hits created by the new contracts granted to most of the UFA RBs this season (we don't know about Burkhead's new contract yet).
That's a solid RB base to work from, and the unit has only one spot to fill. That's really the extent of the "problem" that currently needs to be solved, and it's not as big a problem as having two spots left to fill.
There are several ways in which filling that final spot that can be accomplished, and I think the odds are high that the Pats will try (or at least, investigate) all of them thoroughly. Whatever happens, whatever "new guy" ends up being selected for the final-53, because there's already a solid base in place, he won't need to immediately produce at the level that Lewis did for the last ~2/3rds of the 2017 season, nor should he be expected to.