The Bills confirmed that Spiller was back on the field and in pads via Twitter. Spiller has sounded unsure about his Week 4 availability since injuring his shoulder in last week's win over the Cleveland Browns, but this can't be taken as anything other than a step in the right direction for the third-year tailback.
Jackson, meanwhile, is practicing for a second straight day despite telling reporters this morning that he was experiencing more pain and soreness in his sprained left knee than he had anticipated following Wednesday's practice. Still, he's been allowed back onto the field, and the sentiment remains that he'll be available against the New England Patriots - even if his reps are limited, and even if he's wearing a knee brace.
Both running backs will likely be listed as limited participants today - but if both players are able to practice again on Friday, the chance exists that they'll have both at their disposal for this weekend's ultra-important divisional game.