Jay Cannon

USA TODAY Sports

As the 2018 Major League Baseball regular season comes to a close, we can look back on the year that was.

Here are some of the biggest surprises – for better or worse – from the past six months of baseball:

Blake Snell: The ace

With a 6-4 frame and knee-buckling stuff, Blake Snell always had potential. He came into the league in 2016 as a top prospect, posting a 3.54 ERA in 19 starts as a 23-year-old rookie. It wasn’t inconceivable that he could blossom into frontline starter for the Tampa Bay Rays at some point in time.

But not many people expected this.

With one more start scheduled, Snell leads the American League in ERA (1.90), wins (21) and Baseball-Reference’s calculation of WAR (7.0).

The AL Cy Young race essentially has dwindled down to the 25-year-old Snell and Boston’s Chris Sale, two aces with similar profiles. Snell won't reach 200 innings, but Sale is way behind (153⅓ IP) and that's what likely will decide the award in Snell's favor.

Oakland A's: Postseason bound

With a 96-63 record and a stranglehold on one of the two AL wild-card spots, the Athletics have made the transition from a feel-good, surprise team to a legitimate contender in a stacked AL field.

Pitching was a question mark coming into the season, but just about everything that could have gone right for the A’s, has. Trevor Cahill (3.91 ERA) and Brett Anderson (4.42) rebounded nicely; meanwhile, 25-year-olds Daniel Mengden (4.05) and Frankie Montas (3.88) have pulled their weight.

Of course, having the league-leader in home runs on the roster doesn't hurt either. Already one of the league's best pure power hitters, Khris Davis enters Thursday with career-highs in home runs (47) and RBI (121).

Atlanta Braves: Ahead of schedule

The early arrival of the rebuilding Braves has been surprising and exciting to watch. After averaging just 69 wins from 2015-2017, the Braves exploded into contention this year, running away with the NL East down the stretch.

Rising stars Ozzie Albies (21 years old) and Ronald Acuna Jr. (20) have gotten much of the praise in Atlanta this year, and rightfully so. Through Wednesday, Albies was hitting .264 with 24 home runs and 72 RBI. Meanwhile, Acuna has thrust himself towards the front of the NL Rookie of the Year running with a .289 batting average, 26 home runs and 60 RBI.

The contributions from veterans Freddie Freeman and Nick Markakis can’t be overlooked. Freeman has put together another trademark season with 23 home runs and 95 RBI. Markakis is hitting to the tune of a .301 average with 14 home runs and 93 RBI.

Add strong performances from starting pitchers Mike Foltynewicz (2.88 ERA), Anibal Sanchez (2.96) and newcomer Kevin Gausman (2.80 since joining from Baltimore) and the Braves are a force to be reckoned with in the postseason.

Nationals' disastrous season

No team has underperformed this year more than the Washington Nationals. From 2012-2017, they made four trips to the postseason and consistently employed one of the more complete rosters in MLB. With six years of sustained regular-season success and no hardware to show for it, the franchise knew the importance of this campaign, especially with Bryce Harper’s impending free agency.

There's plenty of blame to go around, as the team ranks 12th in batting average (.253), 14th in starting ERA (4.00), and 14th in bullpen ERA (3.97) through Wednesday.

Christian Yelich's MVP-caliber season

Yelich came to the Milwaukee Brewers in an offseason trade with the Miami Marlins and he's been one of the best players in baseball this season. He leads the NL with a .321 batting average, .583 slugging percentage and .978 OPS. He's sixth with 33 home runs and has added 21 steals. All the while, he's started at least 12 games at each of the three outfield spots.

Thanks to an unbelievable second half,Yelich has seized control of the NL MVP race from Javier Baez of the Chicago Cubs. For someone who has not finished above 19th on the MVP ballot, Yelich’s breakout season has been just as surprising as it has been remarkable.

Edwin Diaz: Flirting with history

If someone had told you that a closer would be making a run at Francisco Rodriguez’s single-season saves record of 62, names like Kenley Jansen, Craig Kimbrel or Aroldis Chapman would have come to mind. It probably wouldn't have been 24-year-old Edwin Diaz of the Seattle Mariners.

Diaz quietly experienced success his first two years in the league. He racked up 18 saves with a 2.79 ERA in 2016 and 34 saves with a 3.27 ERA in 2017. What Diaz has done this year however, is anything but quiet.

The right-hander has tallied 56 saves to go with a 1.99 ERA and a 0.79 WHIP through Wednesday and with only a few games remaining , he can overtake Bobby Thigpen's mark of 57 saves in 1990 to move into second place on the all-time list.