Okay, so y'all remember Full House. Of course you do. There were eight-ish regulars on the show (more, if you're counting Nicky and Alex, or Steve, or Comet, or whatever). And those eight regulars were, famously, played by nine actors.
I was young when the show started, and dumb. Do you remember the credits? When little Michelle Tanner popped up, it looked like this (I pulled it from YouTube, because technology):
See that? There's no "and" there. No hyphen. It's just two lines of text. "Mary Kate," followed by "Ashley Olsen." In my little-kid head, I understood that Michelle was played by two actresses, but it seemed to me that she was played by two unrelated girls, one with the surname Kate, the other Olsen. It took me several seasons and some Olsen twins offshoots to realize it.
(Of course, I also thought, as a kid, that TV show flashbacks were real video of the actors from earlier in their lives, and I was impressed the shows managed to prepare so well to have the footage from years and years earlier. And I thought that actors who got married on TV were married in real life, and they had to get divorced after filming. I thought that explained the high divorce rate in Hollywood. I was a weird kid.)
Anyway, casting twins as a single child is not uncommon. Friends did it, too. Heck, just about every show with a little tiny kid does it, just to get through some child-labor issues. But the story — as I always heard it, anyway — was that Mary Kate Olsen was actually a reasonable actress, particularly for comedy, while Ashley was much less competent, really there because of the whole lookalike thing. Is that true? I don't know. But it makes sense — someone had to be better than the other one. That's how it works. So Mary Kate would get the lion's share of the work, and Ashley would come in for breaks, or when they had a Michelle-lookalike cousin from Greece on, or whatever. Whereas individually, neither Olsen twin could fill the entire role, because of talent or because of work restrictions, together they became an unstoppable tiny juggernaut.
The Cardinals have their own Olsen-twin thing going on this season. Through Monday, Matt Adams is hitting .246/.274/.356. Mark Reynolds sits at .247/.322/.395. Neither is doing well (Adams in particular is looking rough). The Cardinals, obviously, have a lot of success stories on the season—Kolten Wong has been great, the Peralta-Carpenter-Holliday triumvirate is doing what they do, and Peter Bourjos is finally hitting like I said he would last year — but the fact that they have the best record in baseball despite Adams, and Reynolds, and Jason Heyward, and Jon Jay all doing what they're doing, and without Adam Wainwright is some kind of voodoo witchcraft.
Anyway, Adams is the pick of the perpetual optimist. He's been a popular sleeper pick for a couple years now, despite a very clear weakness: Dude can't hit lefties. Adams' career line against southpaws is .192/.223/.310, falling to a .150/.190/.150 this year in 21 plate appearances. Sure, he only has 224 career plate appearances against left-handers, and that's hardly a huge sample, but since that was an intentional choice to, you know, keep him from facing lefties, it seems relevant to consider.
The flip side is Reynolds. Now, he's never going to be a batting average guy — he sits at .230 over more than a thousand career games, so I think we can safely say he's not Jose Altuve. And in a tiny sample this season, Reynolds hasn't hit lefties any better than Adams, sitting at .148/.258/.296. But over his career, he's walked enough to reach a .349 on-base percentage and a .454 slugging against lefties, and that's more his talent level than 2015's 31 plate appearances.
There are of course a lot more right-handed pitchers than left. Adams, assuming he can figure some of this stuff out, will get far more plate appearances than will Reynolds. But for those in daily leagues, any time the Cardinals are facing a lefty opponent, you just want to bench Adams. It's popular in those situations to have a fantasy platoon, find a hitter who you can start when you have to bench Adams.
Well, if that's the plan, then why not use his replacement? With very few exceptions, every time Adams is benched, Reynolds will start. If you have, I don't know, Adam Lind as your Adams-other-half, who's to say the Brewers won't also be facing a tough lefty when the Cardinals do?
Full House leaned on Mary Kate Olsen. Ashley was there when the situation wasn't right for Mary Kate. She didn't embarrass herself out there, but she was just the fill-in, the supplement. The same is true for Mark Reynolds. If he's your starting first baseman or corner infielder, well, you have my sympathies, friend. But if your league is deep enough that you're running Matt Adams out there with any sort of regularity — and he's owned in 62 percent of Yahoo! leagues — then you are throwing away a big chunk of games with the Cardinals' "Oh god please don't face a lefty" strategy. Reynolds is only 2-percent owned. Separately, Adams and Reynolds are subpar fantasy players. Heck, so far this year, they've been subpar even in tandem. But if these two hit up to their abilities the rest of the way, Adams+Reynolds could make a very productive duo.