Top five Opening Day storylines

The 2012 Major League Baseball season officially opened last week in Japan, where the A's and Mariners played a mostly forgettable two-game series, and starts Stateside on Wednesday night when the Marlins face the defending World Series champion Cardinals. Thursday, though, is when the season really begins.

That is Opening Day for 13 teams and the first day of the year with multiple regular season games. (Bizarrely, the Marlins play an afternoon game in Cincinnati the day after their season-opening night game at their new ballpark in Miami.) On a day that will be filled with intriguing plot points, here are five things to watch for:

1. Trading places

A year ago at this time, the Red Sox were a popular pick to go deep into October, while the Tigers weren't expected to get there at all. Even as late as mid-July, Boston was in playoff position and the Tigers were not. Then everything changed, and Thursday's Opening Day starters, Jon Lester and Justin Verlander, played central roles in their teams' changes of fortune. After July 20, Verlander went 12-0 in his final 13 starts to help lead Detroit to its first division title since 1987. Meanwhile, Lester was a disappointing 5-5 from that date forward and posted a 5.40 ERA while the Sox went 1-5 in his starts in September, contributing significantly to one of the worst collapses in major league history.

In the wake of that collapse, which saw Boston blow a nine-game lead over the Wild Card leader with just 24 games left to play, the Red Sox cleaned house, declining to pick up manager Terry Francona's option and allowing general manager Theo Epstein to jump ship to the Cubs. What they didn't do was re-stock the rotation that had let them down so badly in September.

As a result, even with the extra Wild Card, the Red Sox are not favored to make the postseason this year, and recent thumb injuries to new closer Andrew Bailey and right-handed ace Josh Beckett haven't improved their outlook. The lack of rotation reinforcements and Beckett's injury put even more pressure on Lester, who, after the collapse, was implicated in the trumped-up controversy over the team's starting pitchers indulging in beer and fried chicken during games. Boston fans desperate for good news should check out the box score of Lester's final spring training start, in which he threw seven scoreless innings against the Phillies, allowing just two hits and striking out 10 against no walks.

The Tigers, meanwhile, are everybody's pick to win the AL Central. Much of that is due to Verlander, the 2011 AL Cy Young and MVP winner who will be interesting to watch on Thursday coming off a season in which he threw 271 1/3 innings, including the postseason. Other plotlines to follow: the Tigers' debut of Prince Fielder -- Detroit's $214 million free-agent import -- his matchups with Lester, one of the game's best lefties, and Miguel Cabrera's first regular-season start at third base since 2008.

2. Returning aces

Arguably the best pitcher in baseball from 2004 to 2008, the Mets' Johan Santana hasn't thrown a regular season pitch since September 2, 2010 due to an anterior capsule tear in his pitching shoulder, which he had surgically repaired later that month. Santana wasn't able to come back last year, but he hasn't had any discomfort in his shoulder this spring while posting a 3.44 ERA in 18 1/3 innings, not allowing a home run and striking out 11 Cardinals in 11 innings over his last two spring starts.

Santana's velocity is down a bit, but his changeup has looked sharp and is coming in a good 10 miles per hour slower than his fastball. He'll never again be the dominant, league-wide ace he was in his prime, but he should remain an above-average starter for the Mets, who owe him $55 million over the next two seasons (including a buyout for 2014) if he can stay healthy. Taking the ball on Thursday is a huge first step.

Santana's opponent, the Braves' Tommy Hanson, is also making his first start since coming back from injury. His 2011 season ended last August due to a right rotator cuff strain. That prompted the Braves to re-work his mechanics, though he made just three spring starts using the new motion because of a concussion he suffered in a minor car accident in late February.

Still just 25, Hanson has shown flashes of being one of the better young pitchers in the league in his three major league seasons, boasting a 3.28 career ERA with nearly a strikeout per inning and a solid 2.91 strikeout-to-walk ratio. With Tim Hudson due to miss April following November back surgery and the NL East looking more competitive than ever, the Braves need Hanson to have a breakout season this year.

3. Are Stephen Strasburg and the Nationals ready to take the next step?

"Stephen Strasburg: Opening Day starter." If you're a baseball fan, those words should excite you. The top pick in the 2009 draft, Strasburg struck out 14 men in his major league debut in June of 2010, but had Tommy John surgery that September. He returned to the majors for five starts last September and looked as promising as ever, posting 1.50 ERA and striking out 24 men in as many innings while allowing just two walks and no home runs. Now, finally, he's in position to play a full major league season, or at least to max out his innings limit, which is believed to be around 160.

Because of that limit, the Nats may not yet be ready for their close-up. Strasburg will be shut down before the season ends (unless he gets hurt in the middle of it), 2010 top pick Bryce Harper is starting the year in Triple-A, and 2011 break-out slugger Mike Morse is starting the year on the disabled list due to a strained right latissimus dorsi. The number of games that those three play together in the majors this year will be a good indication of just how competitive the Nationals will be.

4. AL playoff contenders vs. pretenders

The addition of a second Wild Card to each league has given new hope to teams that aren't among the game's elite. While the Indians, who flirted with a postseason spot last year and have made some effort to reload for this season, could benefit from it, it's the Blue Jays, their opponent on Thursday in Cleveland, who are the real contenders to take advantage of that extra playoff spot.

Last year, the Indians went 60-74 (.448) after a hot 28-game start that gave them the illusion of contention through the end of July. This spring they lost Grady Sizemore to yet another surgery (back), saw third base prospect Lonnie Chisenhall struggle so badly that he failed to make the team despite starting 55 games at third for them last year and watched Ubaldo Jimenez get cuffed around to the tune of a 7.43 ERA while walking as many men as he has struck out. The Indians didn't have a winning record last year, and I'd be surprised if they did this year, either.

The Blue Jays, meanwhile, posted the best record in spring training this year, which doesn't necessarily mean anything (the A's had the best record in the Cactus League), but the they do appear to be an up-and-coming team. Their lineup just keeps getting better. Third baseman Brett Lawrie hit .293/.373/.580 in his first 43 major league games last year and .524 (22-for-42, albeit with just one walk and no home runs) in 16 games this spring. Top prospect Travis d'Arnaud, who should ultimately supplant J.P. Arencibia behind the plate, could be up later this year, and there's still hope that Colby Rasmus could rediscover his talent (though he did look lost this spring). Toronto's bullpen has been restocked with closer Sergio Santos, righties Francisco Cordero and prodigal son Jason Frasor, and ageless lefty Darren Oliver.

The key to the Blue Jays' Wild Card hopes, however, is their rotation. Strikeout artist Brandon Morrow has breakout potential. Prospect Kyle Drabek pitched well this spring and is back in the rotation after pitching his way back to the minors last year. Groundballer Henderson Alvarez, who turns 22 in two weeks, is the best young pitcher no one talks about. All line up behind Thursday's Opening Day starter, 27-year-old lefty Ricky Romero, who was once considered a drafting blunder (he was taken one pick ahead of Troy Tulowitzki with the sixth-overall choice in 2005), but has since emerged as a hard-working ace.

5. Kershaw and Kemp, the year after

Last year, Clayton Kershaw, the Dodgers' lefthanded ace, won the pitching triple crown (leading his league in wins, ERA and strikeouts) and the National League Cy Young award at the age of 23. Their centerfielder, Matt Kemp, fell one home run shy of a 40/40 season (home runs and steals), leading the NL in runs (115), home runs (39), RBIs (126), total bases (353) and OPS+ (171), winning the Gold Glove (undeserved though it might have been) and Silver Slugger and finishing a close second in the MVP voting.

The Dodgers are a shallow team and will need both of their superstars to replicate their performances to have any hope of contention this year. Both made instant headlines on Opening Day last year. Kemp reached base four times, stole one base and scored both of the Dodgers' runs as Kershaw out-dueled Tim Lincecum, striking out nine Giants in seven scoreless innings in a 2-1 win.

Dodgers fans are hoping for a repeat Thursday evening as Los Angeles opens up in pitching-friendly San Diego. Padres starter Edinson Volquez, meanwhile, will have significant expectations of his own to live up to as he make his debut with his new club debut after coming over from the Reds in the Mat Latos trade along with new first baseman Yonder Alonso.