It happens every year: A bunch of players produce way above expectations, and we spend the entire offseason arguing over whether or not the improvement was genuine. Separating the wheat from the chaff when it comes to last year’s breakout performances can be the difference between a championship season and bitter, abject failure for your fantasy team. After all, if you ain't first, you're last.

All week long, I’ll be taking a look at last season’s surprises, be they breakout or bust, and offering my thoughts on each player’s fantasy outlook for 2016. We’ll kick things off with five players ready to be read their rights by the regression police.

Editor's Note: Be sure to head over to our fantasy baseball rankings assistant. We've released a new rankings tool so you can easily filter, sort, and export all sorts of staff rankings in one place - tiered ranks, mixed leagues, AL/NL only, top prospects, dynasty formats, keeper values and more! 

2016 Regression Candidates

Yoenis Cespedes

Cespedes had already put together three solid seasons prior to last year, producing an average 5x5 line of .263/24/78/87/10. In 2015, he was one of the best players in baseball, both real and fantasy. While Cespedes did make harder contact and trim his pop-up rate, expecting a repeat of last year seems like a stretch. His HR/FB% nearly doubled from the previous season and was six points higher than his career mark heading into the season. It’s true that he added nearly 20 feet to his average batted ball distance, but he’d posted a similar mark in 2013 and only managed 26 homers.

Steamer has similar projections for Cespedes and former A’s teammate Josh Reddick, but Cespedes is being drafted about 160 picks earlier, per FantasyPros ADP data. His walk rate, never stellar, has dropped steadily each year and he’s just 21-for-35 in stolen base attempts over the last three seasons. In the early rounds, you want someone who contributes in all categories or is dominant in a few of them. Cespedes doesn’t fit into either category unless he repeats last season, and the smart money says he won’t.

Brandon Crawford

After posting a putrid .584 OPS as a rookie back in 2011, Crawford has improved by that metric every season, culminating in last year’s .782 mark. This progress has been almost solely due to more power, as Crawford’s SLG and ISO have climbed. Last year was a rather large jump as compared to the previous seasons, however. One might cast a skeptical eye toward Crawford’s 16.2 HR/FB% (nearly triple his career mark entering the year), which led to him hitting nearly many homers in 2015 (21) as he had in the previous four seasons (26).

A-ha, another might retort, but gaze upon the batted ball distance leaderboards and there you’ll see Crawford in the top 10. Impressive, to be sure. But excellent research by Chad Young of FanGraphs has shown that hitters who gain at least 15 feet in batted ball distance between seasons tend to give back about half those gains in the following campaign. Crawford’s jump was a whopping 27.3 feet, second-most in all of MLB. Crawford should still be an asset, but he’s unlikely to replicate his 2015 production and won’t come nearly as cheap on draft day.

Odubel Herrera

Herrera was one of the few brights spots for a 99-loss Phillies team in 2015. A Rule 5 draft pick with just 400 plate appearances above A-ball, he hit .297/.344/.418 with eight homers and 16 steals while playing an excellent center field. Unfortunately, there are several red flags here. The biggest is a .387 BABIP. If that number regresses - and it probably will, it's just a question of how much - Herrera will struggle to be relevant in shallow leagues. He struck out in  nearly a quarter of his trips to the plate as a rookie, nearly five times as often as he drew a walk. Those numbers will need to improve to offset any decline in BABIP.

Herrera's eight homers last season were a surprise, given that he'd never hit more than five in a season while in the minors. That's probably the ceiling on his pop. He was also not the most efficient base stealer, getting caught on a third of his attempts. Finally, even though he spent most of the season hitting near the top of the batting order and got on base at an above-average clip, he scored only 64 runs. This is because the Phillies were bad. They will probably be less bad this season, but they still project as the worst offense in the game. Oh, and Herrera lost his middle infield eligibility as well, which takes a big chunk out of his fantasy value.

Hector Santiago

Regular readers of my work (hi, Mom!) will recall that Santiago made regular appearances in my weekly column on starting pitchers - but not the good kind, like you want. He entered the All-Star break with a sparkling 2.33 ERA, despite an FIP a whopping two runs higher. This was mostly due to an absurd and unsustainable strand rate. When that number began to normalize in the second half, Santiago resumed being the middling pitcher he's always been.

Granted, the man has made a career out of outpitching his peripherals (career ERA-FIP of 0.99), but even that hasn't helped him to be more than a capable back-end starter. That has value in real life, but not a whole lot of utility for your fantasy squad. Santiago's iffy control and vulnerability to the long ball make him strictly a streaming option outside of deep or AL-only formats.

J.A. Happ

Happ was a mediocre pitcher having a mediocre season for a mediocre Seattle Mariners club. Then he got traded to the Pirates at the deadline and suddenly was doing a credible Clayton Kershaw impersonation. In his 11 starts for Pittsburgh, Happ struck out over a batter per inning, dropped his BB/9 below 2.00 and posted a 1.85 ERA. He parlayed this run of inexplicable dominance into a three-year, $36 million contract with the Blue Jays.

Unfortunately for Toronto, they should expect more of what they saw in 2013 and 2014 when Happ was on their team (4.39 ERA, 1.37 WHIP) than the form he flashed in the City of Bridges. Happ might have picked up a thing or two from renowned pitching coach/demigod Ray Searage while with the Pirates, but he won't be able to take PNC Park with him. Home runs, long an issue for Happ, are likely to be a problem for him now that he's again making half of his starts at Rogers Centre. Can't blame the guy for taking the money and running, but his 2016 outlook would have been quite a bit better had he stayed in a pitcher's park.

MLB & Fantasy Baseball Chat Room

[iflychat_embed id="c-12" hide_user_list="yes" hide_popup_chat="no" height="400px"]