By AJ Cassavell

On Tuesday, the White Sox announced themselves to the baseball world as contenders when they traded for Jeff Samardzija. Having already improved their lineup (Adam LaRoche) and bullpen (Zach Duke and David Robertson), they added the former Cubs and A's righty to complement left-hander Chris Sale, giving them what all teams want, but few actually have: a dominant 1-2 punch at the top of the rotation.

That the White Sox duo features one right-hander and one left-hander is an added bonus. Sale's three-quarter delivery makes him one of the toughest pitchers on left-handed hitters in baseball, while Samardzija's imposing 6-foot-5 frame makes him a nightmare on righties.

Meanwhile, their crosstown rivals were busy building a formidable lefty-righty one-two punch of their own, as the Cubs signed Jon Lester to a six-year, $155 million deal to help bolster a rotation currently led by Jake Arrieta.

Add in the fact that opposing teams will likely have to face the pair on back-to-back nights, and it's hard to see hitters developing any rhythm. Should the White Sox or Cubs find a way into the postseason, the Sale/Samardzija and Lester/Arrieta combo will make opposing managers miserable with matchup problems.

But where do these new left-right dynamic duos rank among baseball's best? Let's take a look.

10. Tampa Bay Rays: Archer/Moore

The 2014 Rays produced a dud of a season, before losing their well-respected manager and general manager in the offseason. So it's understandable that they've mostly been written off in the American League East. But if Matt Moore can return healthy from his April Tommy John surgery, the Rays will have a pair of very talented young aces entering their age 26 seasons -- and both are under team control for a long time. Righty Chris Archer has quietly put up a 3.28 ERA over the past two seasons in the vaunted AL East. And Moore was 17-9 with a 3.29 mark in 2013 before missing most of the '14 campaign. Add Alex Cobb, Jake Odorizzi and Drew Smyly to the mix, and the Rays have a deep, young rotation that could be very good very soon.

9. Texas Rangers: Darvish/Holland

Yu Darvish and Derek Holland essentially combined to make up one Rangers ace in 2014. They were never on the active roster at the same time. Darvish, the righty, missed the season's final month and a half with an elbow injury after being his usual dominant self for most of the season. And Holland was brilliant in September, posting a 1.46 ERA and a 1.05 WHIP in six outings after missing the season's first five months because of a freak knee injury he sustained while playing with his dog. (Yes, it was too bad we didn't get to see Holland pitch for most of '14. But at least some good came of the injury thanks to http://dfw.cbslocal.com/2014/12/08/derek-holland-wrigley-wish-fans-a-safe-happy-holiday/" this holiday video Holland made>, with no shortage of ugly sweaters or dogs wearing antlers.) Anyway, if Holland and Darvish can both stay healthy and effective in '15 -- a bigger "if" for Holland than Darvish -- they'll form a very formidable 1-2 punch.

8. Oakland A's: Gray/Kazmir

At some point around late May or early June of last season, Sonny Gray and Scott Kazmir would have been at or near the top of this list. But things didn't exactly go as planned for Gray and Kazmir in the second half of the season -- and as a result the A's found themselves blowing a six-game division lead and fighting for their Wild Card lives until the season's final day. At the end of May, the duo each sported an ERA lower than 2.40. Gray went through his rough stretch in August, losing four straight starts, before regaining his groove by season's end. Kazmir, however, never quite got that rhythm back, with a 6.05 ERA in August/September. He remains a question mark heading into the 2015 season.

7. New York Yankees: Tanaka/Sabathia

Regardless of what the Yankees said out loud last offseason about Masahiro Tanaka projecting as a No. 3 starter, they didn't mean it. They had grand visions of Tanaka and his southpaw counterpart CC Sabathia leading the rotation in the Bronx for years to come. And for the most part, Tanaka held up his end of the bargain -- at least until he missed two months of the season with elbow issues. Before he blew up in Cleveland in the start that led to his injury, Tanaka had a 2.27 ERA and was garnering consideration not just for Rookie of the Year, but for the AL Cy Young Award. As for Sabathia, no one is confusing this version of him with the Cy Young-caliber pitcher from 2007-09. But the Yankees are at least hoping he can return healthy from his knee injury and turn around the ugly 4.87 ERA he has posted over the past two seasons.

6. Pittsburgh Pirates: Cole/Liriano

More than anyone on this list, the Pirates have a pairing of two pitchers who couldn't be more different. Gerrit Cole, a young, flame-throwing right-hander threw his fastball 76 percent of the time and for an average velocity of around 95 mph. Francisco Liriano, a veteran lefty, threw nearly as many sliders (843) as fastballs (902) in 2014, according to FanGraphs' Pitch f/x system. But regardless of the methods, both get results. Cole, the top overall pick in the 2011 Draft, has put himself on the brink of ace-dom in the past two years. Liriano's years as a true ace may be behind him, but he's been reliable enough for Pittsburgh (23-18, 3.20 ERA in two seasons) that the Bucs re-signed him to a three-year deal on Monday.

5. Chicago Cubs: Lester/Arrieta

Until around 1 a.m. Wednesday morning, this list began with a nice, tidy paragraph about Jake Arrieta and Travis Wood at No. 10. I even started it with: "Expect the Cubs to skyrocket into the top five if they can land Jon Lester." Well, the North Siders got their man, and here they are at No. 5 on our countdown. Arrieta posted one of the more underrated pitching seasons in baseball last year with a 2.53 ERA and a 2.26 FIP (essentially ERA adjusted for league average defense and luck on balls hit in play). Lester, meanwhile, finished fourth in Cy Young Award voting in the AL, and his presence in the Cubs' rotation as the ace, seems to put everyone else in their proper place with Arrieta at No. 2, Wood at No. 3 and Kyle Hendricks at No. 4.

4. San Francisco Giants: Bumgarner/Cain

Without knowing what the Giants are going to get from Matt Cain in 2014, it's hard to rank them in the top three. If they get the '09-12 version that never finished with an ERA above 3.14, they've got one of the best tandems in the league. If they get the '13-14 version, well, they've still got Madison Bumgarner. There's no need to recount Bumgarner's masterful October here. By now, you know the story. He's cemented himself atop the rankings of "best clutch pitcher alive." If Cain can fully recover from elbow surgery that forced him to miss the second half of the season, the Giants should once again be on the short list of World Series favorites.

3. Detroit Tigers: Price/Verlander

In 2012, David Price and Justin Verlander staged one of the more intriguing Cy Young Award debates in recent memory. Price won it, but the pair had established themselves as the two premier aces in the American League. Two years later, they haven't exactly fallen off the map, but there are serious questions entering '15 -- specifically for Verlander, who posted a 4.54 ERA last season and struck out just 159 hitters in the process. He seems to have lost what was once his greatest weapon -- his ability to get swings and misses. Price still has that weapon. He led the AL in strikeouts with 271. But he also gave up a career high 25 home runs and was just 4-4 with a 3.59 ERA after being dealt to the Tigers. If both can return to their old form, the Tigers are World Series favorites. If neither can, don't be surprised if they're sitting at home in October.

2. Chicago White Sox: Sale/Samardzija

If Sale hadn't missed six starts because of a strained flexor muscle in his pitching arm, there's a good chance he wins the AL Cy Young Award in 2014. His numbers certainly projected to match up with those of Corey Kluber and Felix Hernandez. Simply put, you can probably count on one hand the number of pitchers worth taking ahead of Sale -- and you might have a finger or two left over. Samardzija isn't quite the ace that Sale is, but he's still an ace on about half the teams in the league, coming off a year in which he posted a 2.99 ERA and a 1.07 WHIP -- seventh best in the Majors. There aren't going to be a whole lot of baserunners against these two.

 

1. Los Angeles Dodgers: Kershaw/Greinke

It's hard to top Clayton Kershaw and Zack Greinke as baseball's premier 1-2 punch. You could make the argument that they're the best left-right tandem atop a rotation since Randy Johnson and Curt Schilling in Arizona. (The '11 Phillies with Cliff Lee and Roy Halladay were probably better, but only slightly. There's also the Roger Clemens/Andy Pettitte duo in both Houston and New York. And Sabathia plus Roberto Hernandez -- Fausto Carmona at the time -- weren't too shabby for Cleveland in '07.) But that's how good Kershaw and Greinke are. On top of that, Kershaw and Greinke do just about everything well. They'd be No. 1 among tandems of fielding pitchers, and they'd be right at the top when it comes to hitting pitchers, as well.

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AJ Cassavell is a Sports on Earth contributor and reporter for MLB.com. Follow him on Twitter @ajcassavell.