Someone once told me, “There are no upsets in swimming.” This was said immediately after one of swimming’s greatest “upsets” — when Michael Phelps failed to defend his 200 fly Olympic title, losing to Chad le Clos at the 2012 Olympic Games. My friend continued: “The word ‘upset’ implies that a certain person was supposed to win. In swimming, no one is supposed to win. There’s no fluke ball bounce or last second Hail Mary. First person to the wall wins, and that person was always supposed to win.” 

This weekend’s Arena Pro Swim Series at Mesa is officially a little more than two months outside of the biggest domestic swim spectacle: The Olympic Trials. Two months is but a blip, a season’s worth of blossoms and rains, long mornings and stormy afternoons. Two months from now, we will celebrate the next batch of Olympians to represent our nation, and many will ogle over those Trials results, the winners, runners-up, and 3rd place finishers, and ponder: “Whoa. That race was an upset!”

And yet, was it really? 

Spring shapes the world in slow increments: A dogwood buds, a tulip sprouts. And yet these things did not mysteriously manifest from nowhere. They were planted and cared for, watered and sunshined, and grew and sprouted, so at the right moment, at the right time, they could bloom. 

Two months: The buds have formed and the trajectory and momentum is taking hold. This weekend, as numerous Olympic champions face off against another batch of America’s best and up-and-coming youth, the final swim season of the Olympiad commences. 

As always, here are your 5 Storylines… 

1. Two months away
As alluded above, two months is not much time. For many swimmers at Mesa this weekend, two months is a 50 freestyle — it’s a sprint when compared to the decades of training that preceded.  What’s new this time around? Perhaps more than ever before, previous Olympic veterans are training longer (and faster) than in previous Olympic cycles. Phelps, Lochte, Grevers, Ervin, Coughlin… When was the last time so many 30-year-old-plus Olympic champions were still on the scene? While these names are expected to perform two months from now, we’re unsure what potential challengers are on the horizon. NCAAs gave us a taste of what’s to come, and now, entering long course season for all, we’ll begin to see new names mix with old, fresh and veterans intermixing, competing, and battling. 

2. Lochte vs. Phelps in the 200 IM
It’s been the Bird vs. Magic of our generation. Lochte vs. Phelps in the 200 IM is once again on the schedule this weekend. You won’t want to miss it. Two of the modern era’s best all-around swimmers square off: Could this be the most anticipated race of the summer? Four years ago, I thought this was the last time ‘round. Now, who knows? Maybe we’ll see them again in 2020, 2024, 2028…. Or maybe not. Doesn’t matter. It happens this weekend, and that’s great for the sport. 

3. Back to long course
Speaking of anticipated races, now that the short course season is officially over and done with, and NCAA swimmers are beginning to calibrate towards long course, will we see NCAA swimmers begin to accelerate towards Trials? Remember: Many veterans practice regularly in long course pools. But many college programs train in short course yards. It’ll be interesting to see all programs shift training focus back to long course, and to Trials, and what kind of ramifications that has on the overall landscape. As more NCAA swimmers become more comfortable with long course racing and training, I imagine the growth will accelerate much faster than anticipated. And that’s good. Because time is running out. 

4. Men’s 100 fly: No Phelps, but an assortment of challengers
Conger. Phillips. Lochte. Andrew. The men’s 100m butterfly is perhaps Michael Phelps’ best event, and yet, considering the plethora of potential challengers in this short sprint (one that Phelps has almost lost before), this summer, he may face the most competitive overall sprint butterfly field yet. Be sure to watch out for Jack Conger, who recently impressed at NCAAs. 

5. Franklin, Hosszu, Coventry, 100 back
On the women’s side, Missy Franklin and Katie Ledecky are back in the pool. Yet, the race that most intrigues is the 100m backstroke. There, Franklin will battle Katinka Hosszu and Kirsty Coventry, 2004 and 2008 Olympic champion in the 200m distance. Franklin has gone professional and also switched training locations to mimic her pre-2008 routines. Expect Franklin to pull out the win, and others to try their best to catch her. 

Be sure to tune in to NBC Sport Network's tape delayed coverage on Thursday and Friday night. Check local listings for time and channel in your area.

All sessions will also be streamed live at www.usaswimming.org