For the purists, nothing beats the Outdoor Nationals.

The long awaited summer tradition starts Saturday as Round 1 of the 2018 Lucas Oil Pro Motocross Championship series begins at the 50th annual Hangtown MX Classic just outside Sacramento, CA. Hangtown, also home to a state park, has opened the National's season the last three years and 11 of the last 14 years.

And if the last four years indicate a pattern, expect Ken Roczen to emerge victorious. Eli Tomac and Roczen have traded back and forth on wins since 2014 with the winner of Hangtown going on to win the 450 class Championship three of the last four years. This year proves a bit different though as Roczen returns to Motocross for the first time since 2016 and also recovers from a devastating broken hand incurred a few months ago in Supercross marking the second straight year his Indoors series was cut short because of injury.

Eli Tomac is on title defense for the 2018 Motocross season

Tomac the defending Champion, once again enters the Motocross season coming off a disappointing Supercross year he was widely expected to dominate. He did mostly, taking seven wins but an opening round crashed put him in a deep hole he never recovered from and instead Jason Anderson lifted the trophy at year end. Anderson, however, has never won a Motocross Championship, in either class, and his last two years were cut short because of injury.

Marvin Musquin finished second last year

Then you have Marvin Musquin, a bridesmaid to Tomac in 2017 pushing the title fight to the final round thanks to six straight Moto wins near the end of the season, and he played bridesmaid to Anderson in Supercross this year, also making a season ending run that forced Anderson to clinch in the final round. Playing second fiddle eventually gets old and if not for a knee injury near the mid-point of last season Musquin would certainly ride the #1 Plate on Saturday.

Ken Roczen has not raced Motocross since his 2016 Championship season

Blake Baggett, the 2012 250 Class Motocross Champion, had a career 450 year last year finishing two points back of Musquin and he too can claim "if not for" a thumb injury he might ride the #1 plate on Saturday. Despite that injury that required taping his thumb to the grip, Baggett finished in the Top 10 for every Moto except one last year.

All five, if healthy for the duration, have a chance to turn the 2018 Motocross season one for the ages. Add in a few more legitimate podium threats like Justin Barcia, who finished fourth in 2016 and third in 2015 just six points back of second-place Roczen, you have the potential for a vicious musical chairs routine . Barcia rode lights out to start the Supercross season until he was landed on in a Heat race causing a broken hand. He returned a few weeks before season-end and will line-up on Saturday.

Justin Barcia finished 13th last year

Elsewhere, Dean Wilson posed another podium possibility as he turned in a career season last year taking fourth. Unfortunately, his season ended last week after tearing his ACL in a practice crash. And Broc Tickle was expected to show signs of improvement until a failed urine test ended his Supercross season and quite possibly his career. He provided an update this week that the Switzerland-based oligarchy let him know the Sample B test confirmed the first results. He will not be lining up Saturday.

Regardless, every round could turn into a wild, action-packed spectacle with anyone's guess for who emerges victorious.

Jason Anderson finished 10th last year despite missing half the season

That's if everyone can stay upright. Barcia's season derailed last year. Josh Grant who started the 2017 season with three straight third-place Motos bailed after injury as he did the year before and he's now getting a late start to the Outdoors after coming off a shortened Supercross season when he broke his right leg at Round 7. Justin Bogle won for the first time in the 450 class last year and took a second Moto win but had an injury tattered Supercross season and might not line-up for a few more weeks. Cole Seely, who finished fifth last year might call it a career after a brutal crash a few months ago ended his year. Christian Craig takes his place on the Honda HRC team. Finally, Cooper Webb enters his second season on the big bikes after winning back-to-back 250 titles but a broken leg sustained in April keeps him from lining up on Saturday and he plans to take it week-by-week in terms of a return.

Zach Osborne returns to the 250 class to defend his title

In the 250 class, defending Champion Zach Osborne brings more than enough confidence to take this title again as he successfully defending his 250SX East class Championship in Supercross two weeks ago. Osborne pretty much had his way with the 250 field last year taking the Championship early as Jeremy Martin finished second, 81 points back. Osborne, who originally was planning to move up to the 450 class, gets a chance to ride the #1 plate and offers the safe bet to repeat.

Jeremy Martin finished second last year but posted a DNF in the first Moto

That's if Martin continues to search for his moxie left behind after repeating as Champ in 2015. Martin made a solid run at the East title in Supercross which should help bridge some confidence lost in an injury-shortened 2016 and last year when his season got off to a bad start after his dirt bike died in the first Moto at Hangtown.

Alex Martin also comes into the season healthy after a Supercross season cut short by injury. He was the only rider to give Osborne some pressure last year until a late season practice crash ended his year and Championship hopes. Martin, brother to Jeremy, finished second to Webb in 2016. Aaron Plessinger finished fourth last year but perhaps has a Championship hangover to fight after grabbing his first title a few weeks ago when he won the 250SX West class by two points over Adam Cianciarulo. Plessinger has finished fourth, fifth and sixth the last three years, respectively.

Alex Martin finished eighth last year

Speaking of Cianciarulo, he won't challenge anyone this year as he opted to repair an ACL after the Supercross season. He finished third last year including a stellar 1-2-2-2 finish to the season. Additionally, Martin Davalos remains sidelined thanks to some herniated discs and MCL surgery in April.

Austin Forkner, who chased Osborne and tied him in points midway through the Supercross season before breaking his collarbone, enters his third year (already!) and if healthy should contend for podiums every week. He finished fourth his rookie year and was considered a Championship contender last year but mostly had an up-and-down season until a concussion ended his year. Chase Sexton, who won Rookie of the Year for the 250 class in Supercross, won the honor last year in Motocross after finishing 12th overall. He enters the season with as much hype as Forkner did for his second year.

Aaron Plessinger finished fourth last year

There you have it. If Supercross offered any insight expect some surprises this summer (and we don't mean James Stewart lining up or Ryan Dungey coming out of retirement. BTW, did you know Dungey never won Hangtown?), perhaps some payback or two, a few injuries and hopefully a title fight resolved at Ironman three months from now.

The 2018 Motocross season officially starts with a 1:10 p.m. (PST) Moto 1 gate drop for the 250 class on Saturday at Hangtown in Rancho Cordova, CA. MAVTV airs the first Motos of both classes live and NBCSN picks up the second Motos on tape-delay starting at 5:30 p.m. (PST).