Burkhead, Gillislee and White all got paid and I just dont see the 4th RB as a lock and paying White and not Lewis would suggest that Lewis is the 4th RB. I still think he will make the team but im not going to be floored if Bolden or someone else makes it over him because the 4th RB is either going to be inactive a lot of games or play ST.
Could be that a 4th RB isn't a lock. However, the last time they carried only three was 2007.
In 2012 & 2013 they had 4 RBs including Bolden (UDFA). Those were Bolden's first two seasons and, although he was used extensively on ST, he was also used a fair amount at RB:
... 101/555 (4.9 ypa), 5 TDs rushing
... 23 catches on 31 tgts (74% catch rate) for 163 yards
His extensive use on ST as the 4th RB was likely possible because he's a relatively big guy. Sizes of the RBs on the current 90-man roster are ...
Burkhead, 5102/214
Gillislee, 5111/208
White, 5100/205
Foster, 6000/195
Lewis, 5080/195
Bolden, 5017/225
LeShun Daniels, 5107/225 (not quite as athletic as Bolden, but close in some ways).
The point being that - if either Lewis or Foster is the 4th RB, they very likely
won't be playing the coverage snaps (blocking and tackling) that Bolden does. Burkhead obviously
could, but $3.15M seems an awful lot for a 4th RB/special-teamer (3x what Bolden has been getting), so I have to guess that the Pats expectations for his participation as an RB are much higher, and they seemed fairly aggressive going after him. I suppose it could shake out that way, though ...
Gillislee
White
Lewis/Foster
Burkhead (4th RB/ST)
This would be similar to 2012 & 2013, and could allow the Pats to keep a 4th TE or a 6th WR (not including Slater, of course).
Or, it could end up ...
Gillislee + Burkhead sharing lead carries
White + Lewis or Foster as 3rd-down/receiving back
Bolden (or Daniels) as deep reserve RB/special teamer
In terms of salary cap ...
Burkhead - $3.15M hit, $1.1M dead money (if cut)
Lewis - $1.49M hit - $200k dead money
Bolden - $695k hit, $50k dead money
Foster - $540k hit - zero dead money
Daniels - $465k hit - zero dead money
Training Camp will ultimately tell the tale.