The A's lost 87 games in 2017, after having lost 93 and 94 games in the two seasons before that, and so we're not here to tell you they're going to be the favorites in the American League West in 2018. Not with the defending World Series champion Astros and their potentially historic lineup still there, not with Shohei Ohtani, Ian Kinsler, and Zack Cozart joining Michael Trout with the Angels, and not with the Mariners and Rangers trying to compete this year as well. It's a tough journey in a tough division.
But the A's, somewhat quietly, played .500 ball over the last three months of the '17 season. They may have unearthed two bona fide young stars in first baseman Matt Olson and third baseman Matt Chapman, who, along with elite slugger Khris Davis, made the offense one of baseball's best in the second half. Several of the prospects from the trades the club has made over the last few years are arriving in the bigs, and it just added three relievers who rate very highly in a Statcast™ metric.
The A's won't be the best team you watch in 2018. They could be one of the more interesting, though, even beyond their slick new green jerseys -- and that's important. Here's why.
Because the new relievers were very good
At the moment, our most powerful Statcast™ metric for pitchers is Expected wOBA, or xwOBA. The idea behind it is very simple: It combines both amount of contact (real-world strikeouts and walks) with quality of contact (exit velocity and launch angle), which is then expressed on a scale similar to OBP. The Major League average xwOBA last year was .309, and if you look at a leaderboard of the starters with the lowest marks, you will find truly elite studs atop it: Max Scherzer, Corey Kluber, Chris Sale, Stephen Strasburg, and Clayton Kershaw.
That explanation out of the way, let's look at the 254 relievers who faced 100 batters in 2017. All three of the new A's bullpen arms finished in the top 40, which is to say the top 15 percent.
Emilio Pagan -- .241, 17th-best (tied with Player Page for David Robertson)
Ryan Buchter -- .250, 29th-best (tied with Cody Allen)
Yusmeiro Petit -- .256, 37th-best (tied with Bryan Shaw)
Remember, this is a list of relievers that begins with Kenley Jansen, Sean Doolittle, Pat Neshek, Craig Kimbrel, and Andrew Miller. It's an effective way to get to pitching talent, and it is a much better way to look at skill than ERA or saves are. These three new A's relievers did extremely well in limiting dangerous contact and/or piling up whiffs last year.

Petit, for example, had a 101/18 strikeout-to-walk ratio. Pagan whiffed 56 against just eight walks in 50 1/3 innings as a Mariners rookie. Buchter has bounced around a bit more, going from the Padres to the Royals last year and now to the A's, but he was excellent in 2016 as well, putting up a .270 mark that was better than Craig Kimbrel.
What's also perhaps not a coincidence is this: They're all extreme flyballers. Of those same 254 relievers, the trio finished first (Pagan), third (Buchter), and eighth (Petit) in highest launch angle. The Oakland Coliseum, of course, is well-noted for its massive amount of foul ground -- around 40,000 square feet, or approximately double the homes of the Mets and Twins. No relievers induced more popups last year than Petit (first, 32) and Buchter (second, 28). 
The group they join had five pitchers who were above-average (which we'll set as .300 for relievers) in that metric in 2017 as well, in Blake Treinen, Ryan Dull, Santiago Casilla, Chris Hatcher, and Liam Hendriks. That's eight potentially average or better relievers, which ties with the Yankees (who may have the greatest bullpen in some time) and Mariners.

This somewhat intentionally oversells the A's, of course. No one thinks they'll be as good as the Yanks, and they have to figure out why the returning quintet all underperformed their expected marks, especially Dull and his ugly 5.14 ERA. (One potential issue: According to FanGraphs, the 2017 A's had the worst defense in baseball. With a full season of Chapman, and with Davis [-13 DRS] expected to DH, that should improve.)
The point is, they're all still intriguing. Dull's 2016 rookie season was fantastic, with a 2.42 ERA. Treinen somehow walked fewer and struck out more than he did in 2016, yet saw his ERA jump from 2.27 to 3.93. Hendricks had a higher strikeout rate (28.6 percent) than Archie Bradley. It won't all work out, because it never does. There's a lot to like here, though.
Because the offense got good
Of the nine members of the Opening Day lineup, four didn't last through the season (Stephen Vogt, Yonder Alonso, Trevor Plouffe, Rajai Davis) and a fifth was traded this offseason for Pagan (Ryon Healy). Jaff Decker and Jaycob Brugman played a decent amount of center over the year; Adam Rosales played a lot of shortstop. There were a lot of moving parts. Most of them are gone.
It started to come together in the second half. Chapman was installed as the everyday third baseman when he returned from a knee injury in early July, and he hit .250/.327/.516 (123 wRC+) after the break. Olson took over the first-base job in August when Alonso was traded and ended up with 24 homers in only 216 plate appearances. Chad Pinder and Mark Canha played all over.

After the All-Star break, as Olson went on a tear, the lineup was actually a strength. The .330 second-half xwOBA Oakland's bats posted was the third-best in baseball, behind the Cubs and Indians. They were third, also, by wRC+, behind Houston and Minnesota. It was Olson, sure, but it was also Matt Joyce (.270/.340/.549, 133 wRC+), Davis, Chapman, and Jed Lowrie, too. Of the eight A's who had 150 second-half plate appearances, only the departed Healy and catcher Bruce Maxwell weren't average or better with the bat.
In 2018, they'll also haveStephen Piscotty, who was good in 2016 (.273/.343/.457, 116 wRC+) before slumping in '17 (.235/.342/.367, 92 RC+). They'll likely have better defense in the outfield with Boog Powell and Dustin Fowler. This could legitimately be a good lineup.
Because the rotation is deep, kind of
If there's an obvious weakness, it's this. Last season's A's rotation had a 4.74 ERA, and they haven't added anyone new. But it's deep, at least, and it's young. Very young, in fact. In 2017, only one other team had fewer starts coming from pitchers 30 or older than the 10 by Oakland, and neither Chris Smith (nine) nor Cesar Valdez (one) are still with the team.

Due to their youth and, in some cases, prospect history, there's reason to find almost all of them interesting. Kendall Graveman and Paul Blackburn are both extreme groundballers, among the Top 15 in lowest average launch angle allowed by starters. Daniel Mengden threw 35 innings in the second half, and allowed just six earned runs. Andrew Triggs had an above-average xwOBA (.306) that was the same as Gerrit Cole had; Jharel Cottonhad the same xwOBA as Marcus Stroman or Taijuan Walker.
Sean Manaea is there, too, and A.J. Puk, Grant Holmes, and others are coming. The rotation isn't going to be what pushes this team over the edge. But they're all young, and there's some talent, and if two of them pan out and can be part of the next A's playoff team, you'll take that.
It's not that 2018 is the season the A's take over. It's the year they force you to pay attention, once again. For a team on a three-year streak of losing, there's just so much of interest here.