The 2013 baseball season is halfway gone, with teams taking a quick breather this week for the All-Star Game before making a final push to the finish line.

It's been an exciting season so far, with a couple of record-chasing sluggers vying for MVP votes in the American League, a young Cuban defector destroying baseballs in the National League, and a potentially unprecedented doping scandal lurking in the background. Here, a look at nine of the biggest storylines from the season so far:

Chris Davis
The Orioles' Chris Davis has come out of nowhere to become one of the most feared hitters in the game. Davis, who will start in Tuesday's All-Star Game, has homered in each of his last four games. His 37 home runs lead the league, and are the most ever for an A.L. player at the break.

As Fangraphs' Jeff Sullivan notes, Davis is performing exceptionally better than his competition as a power hitter. While a bunch of players are clustered together for the league lead in triples, Davis is creaming everyone in various power metrics, leading those categories by margins comparable to what only players like Barry Bonds and Mark McGwire have ever done.

"Davis is reaching his ceiling, and he's been up there long enough to paint a pretty picture," Sullivan says. "This season is looking a lot like Chris Davis' Sistine Chapel."

Yasiel Puig
The young Dodgers phenom got snubbed from the All-Star Game, but he's electrified the league since being called up midway through the season.

In his first month in the league, Puig racked up 44 hits. In the history of the game, only Joe DiMaggio, with 48, has ever notched more hits in his first month in the big leagues. In his first week alone, Puig hit five home runs and made a couple of sensational putouts from the outfield, drawing comparisons to Roberto Clemente.

Puig, who is now batting .391 with eight home runs, has also played a huge role in turning around the Dodgers. After a terrible start to the season, Los Angeles is back to .500, and just 2.5 games out of first in their division.

Miguel Cabrera
After winning the first Triple Crown in 45 years last season, Detroit's Cabrera is in contention to do it again. His .365 batting average and 95 runs batted in are tops in baseball. His 30 home runs rank second. If not for Davis' historic output, Cabrera would lead in that category, too.

Off the field, a new performance-enhancing-drug scandal has rocked the game. The league is reportedly considering unprecedented suspensions for some 20 players linked to a shady Florida anti-aging clinic, Biogenesis.

Despite a procedurally suspect case, the league is said to be considering 100-game suspensions for Alex Rodriguez and Ryan Braun, among others. Though none of the players named in the case tested positive for PEDs, the league is using the testimony of former Biogenesis head Tony Bosch and whatever paper trail he can give them to nail the accused players.

The Pirates
The Pirates haven't had a winning season since 1992. They now have the second-best record in baseball and, barring an epic second half collapse, should end that ignominious streak this year.

The Yankees
Speaking of 1992, the Yankees are on pace to post their worst record since that year. After an encouraging start, the aging and injured Yankees enter the break at 51-44, good for a .537 winning percentage.

If the team keeps up that pace, they will finish with their worst record since the 1992 squad posted a .469 winning percentage. New York has missed the playoffs just twice since then, and is on track to miss out again this year given the stiff competition in the rest of the A.L.

The Red Sox
On the other side of the spectrum, the Yankees' bitter rivals are enjoying an unexpected revival this season after 2012's historically woeful campaign.

A supposedly retooled Red Sox team crashed and burned in epic, pathetic fashion last year, finishing with their worst record since 1965. The team responded by jettisoning high-priced players and manager Bobby Valentine, and 2013 looked to be a rebuilding year.

Not so. Boston has the best record in the A.L., thanks to the return of a number of key players who missed significant time last year due to injuries. After sitting out all of last season following Tommy John surgery, John Lackey has anchored the team's pitching staff with a 2.78 ERA, fourth-best in the A.L.

Big spenders, big losers
The Toronto Blue Jays picked up just about every good player from the Marlins during that team's latest fire sale, raising their own payroll by more than 50 percent in the offseason. Most analysts predicated the Blue Jays would finally return to dominance, or at least contention, in the A.L. East. Yet Toronto is four games under .500, good for last place in the division.

Out in Los Angeles, the Angels signed the off-season's biggest bat, Josh Hamilton, to a five-year, $125 million deal, one year after signing Albert Pujols to a 10-year, $240 million contract. Both players have underperformed — Pujols' numbers have been declining steadily every year since 2009 — and the team, at five games underwater, is nine out of the wild card race.

Matt Harvey
In an otherwise miserable season, the New York Mets have at least one bright spot in the promising young ace Matt Harvey. In his first full year in the majors, the 24 year-old has a 2.35 ERA to go along with 147 strikeouts.

Harvey is slated to start the All-Star Game Tuesday at the Mets' home park, Citi Field.

But at 41-50, the Mets have the third-worst record in the N.L.