When George Costanza tried to give himself the nickname "T-Bone" in a memorable "Seinfeld" moment, the experiment ended poorly -- as, quite frankly, many incidences of self-appointed nicknames end. Nicknames, after all, are at their best when organically ordained by outside influences, and certainly when they are not merely shortened ("A-Rod") or "y"-enhanced ("Greeny") versions of the original appellation.
So when MLB players were presented with the challenge of assigning themselves a nickname for Players' Weekend, it was a tall task. Thankfully, a great many of them came through courageously, and we'll be spending the weekend saluting their sobriquets.
As we run through this weekend's best storylines, let's start there. ...
1. Players gonna play: The second annual Players' Weekend presented by Valspar today through Sunday, is a celebration of the individuality of these men in the Majors, how they got here and the kid within.
All 30 clubs will participate by wearing vibrantly colored alternate uniforms, designed by Majestic, that resemble what you'd typically see in Little League. Many of the players will be wearing nicknames on their backs and all will be wearing "Evolution" patches on their sleeves that display a player progressing from youth baseball to the bigs with a space for the player to write a thank you to a person or organization that helped him get where he is today.
Are you ready to witness history, the kind of thing chroniclers of this great game will spend generations dissecting and discussing? Because D-backs reliever Brad Boxberger will become the first player (in the modern era at least, because who knows what they were up to pre-1900) to don emojis on his uniform (a box and a burger, of course).
We've also got fun nicknames like Jarlin "the Marlin" Garcia (he plays for the Marlins, in case there was any confusion), Walker "Ferris" Buehler and, naturally, Shane "Not Justin" Bieber.
You'll be able to purchase the game-worn jerseys from Players' Weekend via auction at MLB.com/auctions, with 100 percent of proceeds to be donated to the MLB-MLBPA Youth Development Foundation, a joint effort focused on improving the caliber, effectiveness and ability of amateur baseball and softball across the U.S. and Canada.
2. Elevating: The Cardinals keep going up, up, up in the National League pecking order, so it's only appropriate that they're headed for Denver's high altitude this weekend. And the Rockies have been trending upward, as well, making the three-game series that begins with Antonio Senzatela and Miles Mikolas on the hill at 9:40 p.m. ET tonight all the more enthralling.

While we must make the usual mention that these two clubs could conceivably face each other in the NL Wild Card Game (because that's one of about 1,000 different still-present possibilities for that particular matchup), both the Rox and Cards are capable of winning their divisions outright -- something you would not have assumed when the Rockies were still a sub-.500 squad on July 2 and the Cardinals were dismissing manager Mike Matheny on July 15.
Two big reasons why these clubs remain relevant? Nolan Arenado for the Rockcies and Matt Carpenter for the Cardinals. As of this writing, they rank one and two among NL position players in Baseball Reference's Offensive Wins Above Replacement calculation (Arenado at 4.7, Carpenter tied with Freddie Freeman at 4.6) and one and two in OPS (Arenado at .967, Carpenter at .959). They are central elements of the MVP field, so it will be fun to see them on the same field, and what do you want to bet that Carpenter pads his NL-leading home run total (34) at Coors?

3. Swap, meet: The D-backs are the club the Rockies and Dodgers are chasing in the NL West, and Arizona just took care of business in a soft portion of the schedule while winning seven of 11 against the Reds, Rangers, Padres and Angels. An interesting test awaits this weekend when a Mariners team alive in the AL playoff race comes to town (Erasmo Ramirez and Zack Godley square off in tonight's 9:40 p.m. ET opener at Chase Field).
Let's not forget a big reason why the Mariners are alive -- a trade they made with the D-backs! On Thanksgiving Eve 2016, Seattle shipped Taijuan Walker and Ketel Marte to Arizona for Jean Segura, Mitch Haniger and Zac Curtis.
Marte, 24, is growing as a power hitter and a regular in Arizona's lineup, but Walker went down earlier this season with an elbow injury that required Tommy John surgery (one of many early season setbacks the D-backs had to endure to get to this point). So you'd have to say the Mariners have gotten the better end of the deal, to date. Segura has given them the above-average offensive impact at shortstop and good defense that he gave the D-backs in 2016. The real revelation of that trade has been Haniger, who has blossomed into one of the bigs' more underrated offensive contributors (.837 OPS, 20 homers, 27 doubles).

Anyway, all that matters in the here and now is the here and now. The D-backs are trying to fend off the Rockies and Dodgers, and the Mariners are desperate to erase their deficit in the AL Wild Card race. So there's a lot at stake as these two swap partners meet in the desert.
4. Fier'd up: How are the Oakland A's doing this? The question has been posed many times by many people. The answer is multi-pronged, no doubt. But one element of the A's stunning success in this '18 season is the value they're getting out of some decidedly undervalued starting pitchers. Guys like Edwin Jackson, Brett Anderson and Trevor Cahill have stepped up big for Oakland this season.

The A's latest awesome acquisition on that front is Mike Fiers. They landed him this month when the Tigers put him on waivers. And while Fiers was already having a pretty solid season in Motown (3.48 ERA, 128 ERA+ in 21 starts), of course he's taken his performance to another level with the A's -- a 1.47 ERA with 21 strikeouts, one walk and 11 hits allowed in 18 1/3 innings over three starts.

Fiers' next assignment comes Saturday in Minnesota (7:10 p.m. ET), where he'll look to build off the seven scoreless he threw against the Rangers earlier this week. The A's will follow him with Anderson, who is in the midst of a month in which he's posted a 0.68 ERA over 26 2/3 innings, in Sunday's series finale.
That's not the complete answer to how the A's are doing this. But, yes, it's a pretty good start.