It happened in the span of less than a quarter. Right before the first quarter ended in Sunday's game between the Bills and Vikings, Fred Jackson suffered a groin injury. Nine minutes and 46 seconds of game clock later C.J. Spiller left with a shoulder injury. Both players were carted off the field and were declared out for the game a short time later.

Both Jackson and Spiller were visibly upset as they were driven off the field. Jackson was holding his head in his right hand, while Spiller put his hand over his face with a towel draped over his head.

Spiller sustained his shoulder injury after falling hard at the end of a 53-yard run, the Bills' longest rushing play of the season. He was tripped up on the play by Vikings safety Robert Blanton at the 15-yard line.

The Bills' back immediately grabbed for his left shoulder after the play. After the game head coach Doug Marrone indicated that Spiller will be sidelined indefinitely.

"C.J. [Spiller] will be out for an undetermined amount of time," said Marrone. "I think that's out there already, from what they told me. We're going to look at Fred [Jackson]. We really don't have any timetable on that."

Jackson suffered a groin injury what appeared to be a harmless carry off the right side on a 3rd-and-1 near the end of the third quarter. Jackson may have initially injured his groin two plays earlier on a six-yard catch on first down. Then on the hand-off two plays later he aggravated his groin again on the carry that went for no gain.

Jackson needed assistance to leave the field of play and a short time later was carted to the locker room.

Jackson leads the team in all-purpose yardage. He came into Sunday's game against the Vikings with 472 all-purpose yards, which accounts for almost a quarter of the team's total net yards on offense this season.

Spiller was the team's leading rusher coming into the game and had 340 all-purpose yards on the season.

Before Sunday's game the rushing duo had combined for more than 41 percent of the team's total net yards on offense.

Injuries suffered by both Jackson and Spiller last season were the main reasons why the club signed Boobie Dixon in free agency and traded for Bryce Brown. Those will be the two replacements at running back moving forward if the injuries to Jackson and Spiller are long term.