It's probably been a while since you've read a traditional "buy low, sell high" article.
In today's golden age of baseball analytics, where complex physics and statistics can be boiled down to a few simple indicators accessed instantly using one hand, it's not very often that we (readers, fans, fantasy players) find ourselves in possession of knowledge before the masses. For example, try "selling" Avisail Garcia and his recent .375 wOBA around your league without getting some type of response that includes, "Yeah, but he had a .392 BABIP."
Thankfully, despite all the data available at our fingertips, the one ingredient that will always play a critical role in the mixture of value is the human element of perception, which can swing wildly in different directions, depending who you're dealing with. Today I'd like to isolate a few players whose perception may be impacting their actual value a little more than it should be, which may represent a buying opportunity for savvy fantasy owners prepping for 2018. The good news is that you don't have to stand in line to land these deals, but you will still need to get them early.

Roberto Osuna
Osuna finished third among all relievers last season in K/BB ratio (9.22) and fifth in saves (39). He walked just nine hitters in 64 innings. He pitched the entire season at 22 years old. The last age-22 (or younger) reliever to at least match Osuna's 3.0 WAR in 2017 was Francisco Rodriguez in 2004 (3.7).
I wasn't aware Osuna was so young. I wasn't aware he was so good, either. And for whatever reason (maybe those 10 blown saves), it doesn't seem like his excellence has been cemented in the minds of fantasy owners just yet, as he still seems relatively attainable in fantasy trade discussions. He's not only one of the best current relievers in the game, but seems to be on a very early path to becoming one of the better relievers in the game, ever. I don't think his owners see him in that light yet, so buy now while you can.
C.J. Edwards
Sticking with relievers, the perception of Edwards may be tainted a bit by his performance in the playoffs (11.57 ERA), but that may present a buying opportunity. The tall, thin 26-year-old righty posted his second straight season with a K/9 over 12.0 and a BABIP under .200 in 2017, and he also reduced his HR/9 to below 1.0 (0.81). Statistically, he actually pitched better in '16, primarily due to better control (5.16 BB/9 last season compared to 3.50 in '16), but his stuff is so electric that there's at least somewhat of a chance that his 25 holds in '17 will slowly translate into a few more save chances next year. (The Cubs will likely sign another ninth-inning arm, but again, this is about buying before the market does.)
Edwards Jr. is a guy you can probably get cheaply right now, and buying early could pay off in both great ratios and productive counting stats. If his command takes even a small step forward, Edwards Jr. could finish 2018 as one of the more effective middle relievers in the game.

Aaron Hicks
By no fault of his own, Hicks was overshadowed this season by another Aaron who launched his way to the American League Rookie of the Year Award and finished second in the AL Most Valuable Player Award voting -- Aaron Judge. The switch-hitting Hicks also had a stellar season, finishing the year with a .363 wOBA in just 88 games. Somewhat of a post-post-post-hype breakout, Hicks managed to nearly double his walk rate (from 8.3 percent in 2016 to 14.1 percent last season) and increase his ISO (.209), while somehow keeping his solid-contact rate (18.6 percent strikeout rate) constant. Hicks did most of his damage last year vs. left-handed pitchers and early in the season (April: .431 wOBA; May: .397 wOBA), suffering several nagging injuries later in the summer (he missed all of July).
I don't think the small sample success Hicks sustained last year is a fluke, and I also don't think his potential as an OF3 next year in a great stadium and lineup has caught up to the masses just yet. He's a great cheap outfield target this winter to add to your roster and should be very productive over a full season, if he can keep his power (12 of his 15 home runs came at home in the Bronx). He'll play all of '18 at the age of 28 and should at least be on your radar, if not your roster.

Lonnie Chisenhall
Take almost everything I wrote above about Hicks and now apply it to Chisenhall, who also managed a career year (.369 wOBA) in a shortened season (82 games). Significantly increased walk rate? Check (from 5.5 percent to 9.3 percent). Career-first ISO above .200? Check (.233). Post-post-post hype? Check (first-round Draft pick in 2008).
Chisenhall hit the ball harder (33.7 percent hard-hit rate) last year than any of his prior seasons, and the lefty hitter also made big strides against same-side pitching (.419 wOBA), which supports both his skills growth and profile change. Unlike Hicks, however, Chisenhall is not likely to be slated for full-time outfield duty in Cleveland next season (Steamer projects 97 games), though there is enough to like here that Chisenhall can be scooped up for next to nothing right now in most leagues to play a key OF5 or bench-bat role for your team next year.

Kyle Tucker
Tucker showed up at No. 4 overall on my recent Top 100 Fantasy Prospect rankings and is the only true prospect to make this bargain list. A No. 4 ranking wouldn't normally indicate a buying opportunity, but because I believe there's still a large gap between Tucker's potential (very high) and his perceived prospect value (medium) in most leagues, he's the prospect I recommend targeting most this offseason based on his lower cost to acquire and the actual value he can deliver to your roster.
Tucker is well ahead of the age curve for most top prospects (he finished in Double-A last season at age 20), and he has a resume that indicates success could come quickly on the biggest stage in baseball, potentially as early as this summer. With a potential 70 grade hit tool that includes a solid approach, the sweet-swinging lefty outfielder hit a combined .274/.346/.528 with 25 home runs across two levels this past year.
One impressive note about Tucker is his continued improvement against left-handed pitchers in the Minors:
2015 OPS vs. LHP: .511 
2016 OPS vs. LHP: .790 
2017 OPS vs. LHP: 1.019 (.318/.399/.620 in 148 plate appearances)
In 2013 at age 21, Christian Yelich hit .288/.370/.396 (.341 wOBA) in his debut (62 games), and I can see a similar debut occurring this year and also a somewhat similar career development path for Tucker (maybe with a bit more power long term). That's an excellent player to get your hands on before the rest of your league figures out what to do with Tucker.
A version of this article first appeared at FanGraphs.