What to watch as rest of majors finally get seasons underway

The 2012 baseball season had its third Opening Day on Thursday with six pitching-dominated games and one, between the Indians and Blue Jays, that rolled on for an Opening Day-record 16 innings before finally concluding. On Friday, the 13 teams that still haven't launched their seasons will at long last get their uniforms dirty amid a nine-game slate.

Among those teams are five that made the playoffs a year ago and several others that are expected to be in the thick of the races this year. Here, then, are five stories to follow for the teams who have finally made it to Opening Day.

1. Comeback quests

Three of the American League's most important players -- Justin Morneau and Joe Mauer of the Minnesota Twins and Adam Dunn of the Chicago White Sox -- resume their careers after 2011 seasons that raised serious questions about how much they have left. For Morneau, it appears he will try answering those questions as a designated hitter, as the Twins are worried about another play like the dive he made into foul territory while playing first base last August that re-triggered the post-concussion symptoms that cost the former MVP a year and a half of playing time. The 2006 AL MVP played only 69 games last year and hit just .227/.285/.333 and hinted this spring that if his symptoms re-emerge he may have to retire. Both he and his team should be encouraged by how Morneau finished spring training, putting together a nine-game hitting streak during which he hit .433 in 30 at-bats with three home runs. That was Morneau's best stretch in any type of competition since before his concussion.

Having Morneau at designated hitter also allows Mauer to spend increased time at first base, a position he had never played in camp prior to this year. Mauer, like Morneau a former AL MVP, missed more than three months due to injury last year and saw his numbers even when ostensibly healthy dip far below his established standard, particularly in the power department, as indicated by a mere .368 slugging percentage. Mauer went homerless again this spring, but stayed healthy and hit for a more characteristically high average. The Twins are heavily invested in both players in terms of dollars, years and the construction of their offense. As they go, so goes the franchise. Twins fans will get their first look at the reconstituted M&M boys against Jake Arrieta and the Orioles in Baltimore.

As for Dunn, he wasn't hurt last year, but he played like he was, hitting .159/.292/.277 with just 11 home runs in 496 plate appearances. He, too, has had an encouraging spring, hitting a Dunn-like .263/.408/.596 with six home runs, more than half of his regular season total of a year ago, in just 57 at-bats. Teammates Alex Rios and Gordon Beckham are also looking to rebound from forgettable 2011 seasons and will take the first step toward doing so against Colby Lewis and the Rangers in hitter-friendly Arlington in the first game of the day, a 2:05 p.m. Eastern time start.

2. Aces high

The only Opening Day tilt to pit two men who finished in the top four of their league's Cy Young voting in 2011 against each other is Friday's Yankees-Rays matchup at Tropicana Field, which will see CC Sabathia take the hill for the Yankees against the Rays' James Shields. Shields and Sabathia finished third and fourth in last year's American League voting, respectively, each helping to pitch his team to the postseason, and the Yankees and Rays open this year as favorites to again finish in the top two spots in the AL East and return to the playoffs.

Adding intrigue to this matchup is the fact that these two pitchers locked horns in two outstanding pitchers duels in consecutive starts last summer. On July 10, both men went the distance in the Bronx as the Yankees won 1-0 behind Sabathia on an unearned run that scored on a Shields throwing error. Their combined line in that game: 17 IP, 8 H, 1 R, 0 ER, 2 BB, 14 K. Five days later, in a rematch in Florida, Sabathia again went the distance only to lose 2-1 to Shields, who went 7 2/3 innings, and a pair of Rays relievers.

3. Power shift

Watching the Cardinals play without Albert Pujols in Wednesday night's opener in Miami was a strange experience, and on Friday the Cards will be in Milwaukee where that sensation will be compounded by the sight of a Brewers team that lacks Prince Fielder. The departure of those two sluggers -- Pujols signed with the Angels and Fielder the Tigers in the offseason -- has changed the face of the National League Central, if not the league as a whole, but it hasn't changed their former teams' status as frontrunners in their division.

Opening Day in Milwaukee will pit third-year Cardinals lefty Jaime Garcia, who will be crucial to the Cardinals' season if Chris Carpenter struggles to return from the nerve issue in his pitching shoulder, against Brewers ace Yovani Gallardo. It will also mark Ryan Braun's first regular season game since Fielder's departure and his own doping controversy. Those two factors will put a great deal of weight on Braun's shoulders this season, particularly in the early going, and seeing how he responds will be one of the more compelling aspects of the young season.

4. The champion is now the challenger

The third of three Friday games that match what could be the top two teams in a division against each other will see the 2010 World Series champion Giants take on the team that beat them out for the NL West title in 2011, the Arizona Diamondbacks, in Phoenix. That game also features arguably the day's second-best pitching matchup with Tim Lincecum, the two-time Cy Young award winner who finished sixth in last year's NL voting, facing Ian Kennedy, who finished fourth after a break-out season in which he emerged as Arizona's ace by going 21-4 with a 2.88 ERA.

The Diamondbacks are not only looking for a strong follow-up season from Kennedy, but are hoping for increased offense from full seasons of Paul Goldschmidt at first base and Aaron Hill at second. The Giants, meanwhile, finally seem to have given in to the inevitable and are believed to be pushing Aubrey Huff into the outfield to make room for top prospect Brandon Belt at first base. Belt, who turns 24 in two weeks, is a career .343/.457/.596 hitter in the minors and hit .378/.420/.608 in spring training to force the Giants' hand.

5. Albert the Angel

The best player in baseball is on a new team and will play his first game in his new uniform Friday night when the Royals visit his new digs in Anaheim. My guess is that Pujols' career as an Angel will look like Alex Rodriguez's as a Yankee -- a couple of MVP seasons, perhaps a World Series title, but also injury and decline with many years and dollars left on his contract. It's worth noting that at 32 Pujols is four years older than A-Rod was when he came to the Bronx. Still, the player manager Mike Scioscia will send out to first base on Friday night is a superstar with the potential to finish his career as the greatest hitter in Angels' history.