Stephen Tulloch has said that incidents off the field in the off-season have harmed the Detroit Lions' campaign this year.
Several players were arrested in the off-season, resulting in the team being branded as undisciplined.
The linebacker told NFL.com: "It started in the off-season, spending all that time on all those issues, and that wound up lingering into the season, those distractions, and then you look at it, and last year, a lot of things went our way, we were winning games the way we're losing them this year.
"I think discipline is the biggest issue, that kind of selfishness, it hurts the team. We've had guys hurt the team through their actions, and it lingered. We had Aaron Berry here, we were really counting on him, he gets dismissed, and now you need someone to fill in.
"I try to put my finger on whether there's a bigger problem, but I get lost trying to pinpoint what it is. We need more accountability. Hopefully we can weed that out this off-season."
The Lions made the playoffs for the first time since 1999 last season, but have won just four games this year.