Mike Trout vs. Bryce Harper was a thing for a while there, until Trout made his case convincingly (and historically) clear. Harper vs. Manny Machado was looking pretty good, but, in 2017, with Harper putting up early MVP credentials and Machado starting slowly, it really hasn't been a topic worth debating.
 
So let's usher in some other, more timely MLB player debates. Here are my five current favorites.

1. Best pitcher: Clayton Kershaw or Max Scherzer

If you take ERA+, which adjusts for league and park factors to put a pitcher's performance in context, no starting pitcher has a higher career mark than Kershaw's 159 (or 59 percent better than average). So we can divorce ourselves from our romantic images of the likes of Walter Johnson and Bob Gibson and Sandy Koufax and make a fact-based, non-hot-take argument that Kershaw is the greatest pitcher of all-time.
 
I like to think Bill James, the statistical pioneer who taught us how to remove emotion from the equation and strictly adhere to analytics, is to thank (or blame) for this.
 
Except… wait a minute… Bill James' own formula for starting pitcher evaluation says Scherzer is now ahead of Kershaw!
 
Well, I'll point you to James' own explanation for that ranking, but the gist of it is that he weighs the present more than the past. And in the time since James posted that, Kershaw had a rare clunker (four homers allowed in 6 1/3 innings), and Scherzer took a no-hitter into the eighth. So that only augments James' argument.
 
The more you look at this, the more you have to wonder if James is onto something. Scherzer is four years older than Kershaw, but, going back to 2013, he's been more durable, compiling 999 1/3 more regular-season innings to Kershaw's 919 1/3. He's been statistically better in the postseason (3.74 ERA in 74 2/3 innings to Kershaw's 4.55 mark in 89). And if you had a 2017 National League Cy Young vote right at this very moment (subject to change, of course), you'd have to go with Scherzer over Kershaw.
 
So yes, crazy though it might sound or seem on the surface, this is a legitimate discussion. You've got to hand the ball to one guy to win one game. Who ya got?
 
My pick: The best pitcher in baseball is Clayton Kershaw (all I had to do was type the first six words of that sentence, and my computer automatically fills in the rest out of habit). But yeah, this is a fun topic and will continue to be in what might evolve into an NL Cy Young Award battle for the ages.

2. Best rookie: Aaron Judge or Cody Bellinger

If you have a natural aversion to the big-market ballclubs, you might not be enjoying this as much as everyone else right now. Not only are two of the best players in baseball in this 2017 season playing for the Yankees and Dodgers, but they are rookies who have basically remade the reputations of their lineups.
 
Forget the American League Rookie of the Year Award. Judge is your early AL MVP favorite with Trout on the shelf, and he's a threat to not only win the old-fashioned Triple Crown (batting average, homers and RBI) but also the three slash categories (average, on-base percentage and slugging percentage). Oh, and he might break Mark McGwire's rookie home run record (49) while he's at it.
 
Bellinger came up from Triple-A three weeks into the season and might break at least the NL homer record (38, held by Wally Berger and Frank Robinson), anyway. He has the most homers of anybody in MLB since his April 25 promotion and, in a related development, the Dodgers have been the best team in baseball in that span. He's already had five multi-homer games, and he just became the first rookie ever with a stretch of 10 homers over 10 games.
 
Obviously, we're not in a position where we have to actually choose between Judge and Bellinger, because they're both on pace to take home individual hardware this year. But there was a fun discussion on MLB Network Radio the other day about which player you'd rather have for the next 10 years. Judge is in his age-25 year while Bellinger is just 21, so that's a big plus in Bellinger's favor, though it's doubtful Bellinger will be a high-average guy (and to be fair, no one ever really thought Judge would have as high an average as he does right now). Though Bellinger is excellent defensively at first base and won't hurt you in the outfield, Judge probably has more defensive value.
 
My pick: Judge, if only because guys of his immense stature are so darn interesting (and, at 6-foot-7, 282 pounds, the largest position player in history qualifies).

3. Best young shortstop: Francisco Lindor or Carlos Correa

'Round and 'round we go with this one. Correa rightly edged his fellow Puerto Rican and June callup in the 2015 AL Rookie of the Year race, and there was general industry thought at the time that while Lindor will clearly hold the greater defensive value moving forward, Correa was more likely to one day win an AL MVP Award. Then, in 2016, Lindor was the one who made the All-Star Game and got some down-ballot MVP love, while Correa took a slight step back offensively on an Astros team that came up short of October (although it bears repeating that Correa's 2016, in which he had an adjusted OPS+ 25 percent better than league average, was ultra-rare offensive output for a 21-year-old shortstop, and he wound up with a higher Baseball Reference-calculated WAR mark than Lindor did).
 
This season, after the two paired up on the left-hand side of the infield for Team Puerto Rico in the World Baseball Classic, Lindor stormed out the gates with a .309/.380/.638 slash and 16 extra-base hits in April, generating many a breathless dispatch about his improved power and early AL MVP Award chances, all while Correa came out rather lukewarm, by comparison.
 
But the tide -- and the award chatter -- has clearly shifted back to Correa in the time since. Correa's got an OPS+ 44 percent better than league norm, while Lindor's June struggles have dipped him down to average terrain. Surprisingly, Lindor hasn't rated as well in the defensive metrics as he did last year, either.
 
My pick: Lindor is everything you could possibly want in a franchise player. But Correa's still the one more likely to have a Hall of Fame-caliber career (hopefully they both get there).

4. Best closer: Craig Kimbrel or Kenley Jansen

Just a few months ago, the clear answer to this question would have been, "Zach Britton." But we know too well how quickly the conversation can change, especially with regard to relievers.
 
Kimbrel has totally changed the conversation about him. After much justifiable hand-wringing about his late-season command woes last season, he's rediscovered his old Atlanta magic this year. Jansen, meanwhile, hasn't had as many save opportunities (that's why his teammates recently felt the need to load up his locker with some consolation candy…), but it's amazing what he and his cutter are capable of (or, in the case of walks, what they are not capable of).
 
Let's just look at the '17 numbers here…
 
Kimbrel: 20 saves, 0.85 ERA, 31 2/3 IP, 0.442 WHIP, 543 ERA+, 11.8 K/BB
Jansen: 15 saves, 0.91 ERA, 29 2/3 IP, 0.573 WHIP, 462 ERA+, Incalculable K/BB because he's struck out 50 and walked none
 

So… Game 7? World Series on the line in the ninth? Who would you rather have trotting in from the 'pen?
 
Well, in a perfect world, I'd have one of them coming in via bullpen car, but that's another topic for another time. In this exercise, you have to weigh Jansen's possibly historic walk-free zone (the record for most full-season innings pitched without a walk is 21 by Len Swormstedt of the 1906 Boston Americans) against Kimbrel's possibly historic limitation of baserunners in general (the lowest full-season WHIP for a pitcher with at least 40 innings is Koji Uehara's 0.565 mark from 2013). Kimbrel is also, with a .086 batting average against, on pace to destroy his own record for the lowest of all-time (.126, in 2012).
 
My pick: I suppose because Kimbrel ranks first all-time in opponent average (.152) among those with at least 400 innings and Jansen ranks second (.169), that's how I'll rank them here. But this battle of closers could not be, well, closer.

5. Best young third baseman: Nolan Arenado or Kris Bryant

As with the above discussions about Judge and Bellinger and Lindor and Correa, the heart of the matter here is who you'd rather have anchoring your lineup for the next decade or so. (I'll remove Machado from the discussion for now on account of his slow start to '17, but obviously he is eminently capable of complicating matters.)
 
You might not realize it, but Arenado and Bryant were only born 263 days apart. Arenado feels the elder statesman of the two on account of debuting at 22, but they've both got a lot of baseball ahead of them. Bryant's got both a Rookie of the Year and an MVP award on his shelf, but the beauty of the Rockies' newfound contention status is that it exposes a wider audience to the two-way talents and possessed play of the Rockies' franchise face.
 
Before you dismiss Arenado on account of his home park, be advised that his .278/.351/.547 career road slash ain't exactly lacking. And nobody would deny he's the superior defensive player of the two.
 
Here's how they stack up over the last two seasons:
 
Arenado: .297 AVG, .359 OBP, .573 SLG, 127 OPS+, 56 HR, 61 2B, 10 3B, 190 RBI, 9.8 bWAR, 7.9 fWAR
Bryant: .283 AVG, .387 OBP, .542 SLG, 145 OPS+, 54 HR, 49 2B, 4 3B, 130 RBI, 9.8 bWAR, 10.8 fWAr

 
As you can see, Baseball Reference's WAR formula sees this as a much closer comparison than FanGraphs' does. Arenado gets dinged by his home park, though FanGraphs' defense metric (17.8) has him way out ahead of Bryant (11.2). As with each of these discussions, you really can't go wrong.
 
My pick: Arenado is the superior defender, but Bryant probably has the higher offensive ceiling. His rookie-year OPS+ mark (135) was better than any single-season mark in Arenado's career. He rightly ran away with the MVP at 25, and he's just getting started. So he's my guy here long-term, but I would not be at all surprised if Arenado wins the 2017 NL MVP Award.

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Anthony Castrovince is a Sports on Earth contributor, MLB.com columnist and MLB Network contributor. Follow him on Twitter @Castrovince.