For the past two weeks, the have been taking advantage of what appeared to be a loophole in the NFL rulebook, but they won't be able to do that anymore because the league has officially shut things down.Back in Week 13, the Raiders started using a holder for their kickoffs, which was kind of odd, because teams will usually only use a holder when the ball won't stay on the tee due to bad weather. The Raiders past two games C.J. McCollum Jersey were both played indoors, so bad weather definitely wasn't an i sue.Following the team's 27-20 win over the in Week 13, coach Josh McDaniels revealed why the Raiders had decided to use a holder on kickoffs: They were hoping to gain more height from each kick by having the holder put the ball at the top of the tee. By adding height to the kicks, McDaniels was hoping it would make things easier for their coverage team.According to McDaniels, the Raiders checked in with the NFL to make sure their idea was legal and the league initially approved of the team's plan. "They clarified a rule a couple weeks ago, that you're permitted to hold the ball on the top of the tee now, so we've got a good kicker, you can add hang time to the kick, and I think you saw Daniel use that to our advantage," Enes Kanter Jersey McDaniels said Dec. 5, . "As long as you don't kick it into the end zone, extra hang time, put it at the goal line, we' Seth Curry Jersey re further down there, it gives the coverage team a better opportunity to make tackles inside the 25-yard line."As it turns out, the Raiders won't be allowed to do this going forward. According , the league has informed the Raiders that what they were doing was a violation of league rules, so they won't be allowed to do it anymore.So why was it a violation of league rules to use a holder when you're allowed to use one in inclement weather? Glad you asked. Under NFL rules, kickers are only allowed to use a one-inch tee for kickoffs. Most kickers around the league use a version of the tee below when kicking off. 1 Ground Zero Kickoff Football Tee with OnsideNotch College Football R (@CFootballRank) On a normal kickoff, the ball goes in the divot, and that's why it's able to rest in place by itself without a holder. By using a holder, the Raiders were placing the ball on the top edge, which put the football another half-inch or so above the ground.After mulling things over, the league decided the extra half-inch was violating NFL rules since teams are only allowed to use a one-inch tee and this would effectively be using a 1.5-inch tee. The NFL rulebook Harry Giles III Jersey says the ball can be placed on the tee in any fashion, which is why the Raiders thought they were within the rules. If you've ever watched an onside kick, you'll see how creative kickers can get when setting the ball up. For instance, earlier this year, placed the ball on the tee horizontally for an onside attempt against the . Are the on to something? Never Gary Trent Jr. Jersey seen the horizontal ball off the tee for an onside kick, but it worked! Matthew Low (@Mlow930) Although you can set the ball up like that or even have the ball on the ground leaning against the tee, one thing teams won't be able to do going forward is to use a holder to gain an extra half-inch advantage.If there's bad weather, teams will still be allowed to use the holder, but the football will have to be set up in the divot on the tee so that there's no extra height advantage.