It's an adjective to describe something or someone "absolutely necessary" -- you know, the kind of thing that makes a 53-man roster rise or fall.
As I do each offseason, I'm looking to identify the most indispensable players on each side of the football. The offensive list is below. Click on the tab just above for the truly indispensable defenders.
As always, there's a twist on the offensive side: No quarterbacks allowed. Otherwise, they would take up the entire list.
Alright, let's get into it, Schein Nine style. Let the debate begin!
1) Adrian Peterson, RB, Minnesota Vikings
In his nine-year career, Peterson has logged 16 games in four separate seasons, all of which ended with the Vikings in the playoffs. In the five other campaigns? Zero playoff appearances for Minnesota. That, my friends, is indispensable. When Adrian Peterson plays a full season, the Vikings make the playoffs -- plain and simple.
After missing all but one game in 2014 due to child-endangerment charges -- I hope he's truly learned from that disturbing ordeal -- Peterson led the league in rushing last season (1,485 yards) and guided the Vikings to their first division title since 2009.
With Teddy Bridgewater still growing, Peterson is Minnesota's offense. And he racks up these numbers with the opposition designing the entire game plan around stopping him.
2) Rob Gronkowski, TE, New England Patriots
I seriously considered putting Gronk at No. 1, knocking Peterson off his long-held perch. The 6-foot-6, 265-pounder is an unstoppable, uncoverable monster.
I think Tom Brady is the best quarterback in NFL history. And yet, if Brady does indeed serve his four-game suspension at the beginning of the coming season, I'm not ready to concretely give the Patriots a loss in any game. Obviously, a lot of that is because of the genius of Bill Belichick. But I think Jimmy Garoppolo can be OK because he will be throwing to the sure-handed Gronk, the weapon of all weapons in the red zone and on third down.
The tight end has 74 touchdowns in 90 career games, including the playoffs -- talk about a prolific scorer ...
3) Julio Jones, WR, Atlanta Falcons
Matt Ryan trusts Julio Jones. That's his guy. Everything else in the Falcons' passing game is a work in progress. Jones' skill set is simply phenomenal. He caught 136 passes last year for a whopping 1,871 yards -- both NFL highs. Jones is a freak. With him on the field, Atlanta has a chance every Sunday. Without him, fold up shop. Sell ice cream. (And I do like ice cream.)
4) Jordy Nelson, WR, Green Bay Packers
We don't have to project what the Packers' offense would look like without Nelson -- we saw it last season. Sometimes you don't know what you've got until it's gone ... I've long viewed Nelson has a top-five receiver in the NFL, yet this is his first appearance on this annual list. We all make mistakes.
I knew that Nelson suffering a season-ending knee injury in the preseason would be a blow, but I still thought Green Bay would fly. Heck, it all starts with Aaron Rodgers, right? But Rodgers and Co. simply weren't the same without Nelson's ability to take the top off the defense, without his hands, athleticism, smarts, route running and rapport with the quarterback. The Packers dropped to 23rd in total offense last season. Jarring stuff.
With No. 87, Green Bay is a division winner and Super Bowl contender. Without him, Mike McCarthy's team is seriously compromised.
5) Odell Beckham Jr., WR, New York Giants
Yet, with the majestic Beckham, the Giants remain a scary foe. And this guy isn't just a human highlight film -- the overall production is astounding. Over his first two NFL seasons, Beckham has averaged 94 catches for 1,378 yards and 12 touchdowns per year.
6) DeAndre Hopkins, WR, Houston Texans
The Texans wisely brought in Brock Osweiler this offseason, and then built around him and their No. 1 receiver. I think Houston is a legit Super Bowl contender. But if anything were to happen to Hopkins? Forget about it. There isn't enough experience at receiver on this roster. And Hopkins is that good.
Hopkins has been great since entering the league, but he really took his game to another level in Year 3, recording 111 catches for 1,521 yards and 11 touchdowns last fall. And that was with the worst quarterback room in the NFL. I voted Hopkins first-team All-Pro. He's irreplaceable.
7) Todd Gurley, RB, Los Angeles Rams
The Rams lack weapons on offense, have a shaky offensive line and just spent the No. 1 overall pick on a quarterback who went 14-23 in college.
Long story short: L.A. better be able to run the football.
Fortunately, the Rams can do just that -- with authority -- thanks to Gurley, who burst on the scene with 1,106 and 10 touchdowns in an eye-popping rookie year that basically started in October due to a college knee injury.
8) Ryan Kalil, C, Carolina Panthers
Astute football fans know the power of the pivot. The Panthers' center is a true leader and a savvy player.