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3/31/2013 11:26 P.M. ET

Plenty of intrigue surrounds three days of openers

After Sunday's Opening Night action, baseball returns in earnest Monday, Tuesday

Two words: Opening Day.

That pretty much says it all, doesn't it? It's what we've been waiting for since Giants closer Sergio Romo froze Tigers Triple Crown winner Miguel Cabrera for a World Series-ending strikeout on Oct. 28, capping off a San Francisco sweep.

It's what we've been waiting for throughout a longer-than-usual Spring Training that included an undefeated run through the World Baseball Classic by the Dominican Republic and eventful Major League camps for 30 teams with 30 designs on celebrating the way Romo and his brethren by the Bay did last fall.

And now it's here not only on Monday, but it was in full swing Sunday and will carry into Tuesday. The action got under way on Sunday night when the Astros made their American League debut a winning one, beating the Texas Rangers, 8-2, at Minute Maid Park. It continues on Monday with 12 matchups and goes into Tuesday, when six more teams lift the lid on their 2013 campaigns.

All over the great ballparks of the American and National Leagues, we'll witness pregame pageantry as another glorious season gets under way, and while Game No. 1 of 162 might not be the most important in the mathematical sense of things, it's a tone-setter, and if nothing else, it reminds us of what we've been missing in the cold months known as the offseason.

Here are just a few of the many highlights to look out for as the 2013 season officially begins:

Intrigue at Chavez Ravine: Armed with a huge new contract for their heart-and-soul catcher, Bruce Bochy's Giants begin the defense of their second World Series title in the past three years. And the Giants don't look much different from how they ended up last year. They retained the majority of their roster and will field pretty much the same team, with ace Matt Cain on the mound and Buster Posey behind the plate.

They're visiting the Dodgers, who have the highest payroll in the history of the game after a major overhaul that has seen them add All-Star-caliber talent to almost every position. The pressure is on skipper Don Mattingly and starter Clayton Kershaw, who won the 2011 NL Cy Young Award and would love to beat Cain right away for a team that hopes to unseat San Francisco in the NL West.

No limits for the Nats: It isn't surprising to see Stephen Strasburg taking the mound on Opening Day, and maybe there's a hint of symbolism there. Sure, he's the unquestioned ace of the Washington Nationals, who finished last year with the best record in the Major Leagues, but he's also the guy who got shut down before the postseason even started because of concerns about his future after Tommy John surgery kept him out for most of 2011.

Now he's back, and so are the potent Nationals, who feature a terrific pitching staff behind Strasburg and a lineup with one of the most exciting young players in baseball in 2012 NL Rookie of the Year Bryce Harper. They get '13 started against the Marlins at home on Monday at 1:05 p.m. ET.

Red vs. Reds: With the Astros' move to the AL, one thing we'll see a lot more of this year is Interleague Play strewn throughout the entirety of the 162-game schedule. And one of the most interesting matchups as the season begins is the Angels' opening series against the Reds at Great American Ball Park in Cincinnati. The Angels will be flaunting a new lineup featuring their latest high-ticket free-agent signing, outfielder Josh Hamilton, who resurrected his baseball career in 2007 as a member of the Reds after battling drug addiction. It'll be a sort of homecoming for Hamilton, but a real one for the Reds, who won the NL Central last year but bowed out to the Giants in five games in the Division Series and are motivated to do even more damage in October this time around.

Dusty Baker's team will have its 19-game winner of a year ago, Johnny Cueto, on the mound. The Angels will counter with their ace, Jered Weaver, but one player everyone in baseball will be watching will be the first man to stride up to the plate in this opener: Angels leadoff hitter Mike Trout, the phenom AL Rookie of the Year from 2012 who almost took MVP honors after arguably the greatest first season in baseball history.

Justin time: It was perfect timing to have Tigers ace and perennial Cy Young contender Justin Verlander sign a monster contract extension mere days before the defending AL champions' opener, which takes place Monday afternoon against the Twins at Target Field in Minneapolis. Verlander was last seen losing Game 1 of the World Series, following a dominant October that had his Tigers as Fall Classic favorites.

Now the guy's got big-time financial security in his back pocket to go along with that 100-mph fastball, and he's got his buddy Cabrera and Prince Fielder in the batting order, along with Jim Leyland on the bench and an excellent starting rotation that has made his club a prohibitive choice to rule the AL Central once again.

These teams are underdogs? When was the last time we saw a Red Sox vs. Yankees Opening Day game at Yankee Stadium, with Jon Lester pitching against CC Sabathia, and didn't necessarily think either team was favored to even win the division? It speaks to many things, including injuries that have beset Boston and New York, and to the improving AL East and parity throughout baseball.

But don't think for a second that either team can't contend. The Yankees still have pitching, and the Red Sox made sneaky roster moves throughout the winter that very well might pay off. The classic rivalry renews Monday at 1:05 p.m. ET in the Bronx.

Brotherly love: The Phillies won't be at home for their opener Monday, but they'll be visiting a team with postseason hopes and family ties. Brothers B.J. and Justin Upton both ended up in Atlanta in the offseason, and they make up a potent outfield along with Jason Heyward. That has the Braves as many prognosticators' pick in the NL East.

But the Phillies still have the tremendous triumvirate of pitchers Roy Halladay, Cole Hamels and Cliff Lee, and they're looking to get back to their usual prominence after not making the postseason in 2012. It'll start with Hamels vs. veteran Braves starter Tim Hudson at 7:10 p.m. ET at Turner Field.

A Royal plan: Kansas City made a huge statement in the offseason with a complete starting rotation overhaul that brought in James Shields, Ervin Santana and Wade Davis, and brought back Jeremy Guthrie. Shields and Davis, of course, came to the Royals in a trade with Tampa Bay for Kansas City's top prospect, slugger Wil Myers.

Shields will be counted on to do what he does best: pitch well over 200 innings and be the horse, the prime-time performer they call "Big Game James." Against the improving White Sox and their young ace, left-hander Chris Sale, Shields will be called upon to do it right away as his team's season kicks off at U.S. Cellular Field in Chicago at 4:10 p.m. ET.

Elsewhere around baseball, we've got the AL West champion Oakland A's trying to prove last year wasn't a fluke, starting it off against the refurbished Mariners and their newly extended ace, Felix Hernandez.

We've got the Cardinals visiting Arizona on Monday and leading off with the recipient of another huge contract extension, franchise right-hander Adam Wainwright, who will pitch against a D-backs club that is looking to sneak under the radar in the NL West with manager Kirk Gibson.

We've got East intrigue galore Tuesday, when the Baltimore Orioles face the Rays in a battle of serious AL contenders. The Orioles will be trying to build off a stunning 94-win season under Buck Showalter, while the Rays will continue to ride their stellar young pitching to a season of contention that is now expected from Joe Maddon's group.

And as if it were planned this way, with the most drama being saved for the last of the teams' official openers, we'll finally see the 2013 Toronto Blue Jays, who have been picked by many to jump up and win the AL East on the strength of the amazing roster renovation they underwent in a wild winter by general manager Alex Anthopoulos, at 7:07 p.m. ET on Tuesday at Rogers Centre in Canada.

The Jays begin the year against a Cleveland Indians club that looks quite different, itself, with new manager Terry Francona, plus outfield additions Michael Bourn and Nick Swisher, among others. Toronto added star power with Jose Reyes, Josh Johnson, Mark Buehrle, Melky Cabrera, Emilio Bonifacio, and perhaps most significantly, last year's NL Cy Young Award winner, knuckleballer R.A. Dickey.

It'll be Dickey who throws the first pitch for the Jays in 2013, the last pitch in a series of Opening Day starts that we've all been anticipating for a long time.

"It's going to be really loud," Dickey said, "and it should be a fantastic night for all of us."

Doug Miller is a reporter for MLB.com. Follow him on Twitter @DougMillerMLB. This story was not subject to the approval of Major League Baseball or its clubs.