The New York Yankees certainly wouldn't be in first place without stud second baseman Robinson Cano.
Players on each MLB team have specific roles in 2013, but few of them are truly indispensable. Stars like Robinson Cano, Buster Posey and Justin Verlander will be pivotal if their respective teams sustain initial success.
This list emphasizes what these individuals contribute on the field, while acknowledging that intangibles like experience and personality can also make a positive impact.
Before proceeding, understand that there is minimal overlap between indispensable and most talented. The former is characterized by consistency rather than high ceilings. Wins above replacement (WAR) is important but not as much as wins that players provide above their specific replacements within the organization.
Goldschmidt being congratulated after a home run.
Contributions from veterans Jason Kubel and Cody Ross are dictated by the handedness of the opposing pitchers. Both have always posted dramatic platoon splits.
Homegrown first baseman Paul Goldschmidt, meanwhile, serves as a power threat for the Arizona Diamondbacks under all conditions. They sorely need him in the post-Justin Upton era.
Starting shortstops who exhibit both athleticism and baseball intelligence are irreplaceable, and Andrelton Simmons fits that description.
The Atlanta Braves don't have an alternative with such otherworldly defensive skills. Even Simmons' performance at the plate is relatively good for his position.
The Baltimore Orioles lineup is far more imposing than last year's, largely due to Chris Davis and Manny Machado.
That doesn't mean the O's will cruise to lopsided victories. The starting pitchers have had difficulty pitching past the middle innings, thus straining the bullpen.
For the second straight season, Jim Johnson will be summoned in countless save opportunities. Only another great conversion rate can get Baltimore back to the playoffs.
To put it lightly, the Boston Red Sox won't have a dominant bullpen as many in the baseball industry predicted. Andrew Bailey is injured (again), Joel Hanrahan will undergo elbow surgery and Andrew Miller hasn't been nearly as reliable in 2013.
Consistency from the starting rotation can keep Boston afloat, regardless. More so than Ryan Dempster or Jon Lester, undefeated Clay Buchholz gives the Red Sox a great chance to win by not yielding crooked numbers.
The Chicago Cubs would be buried much deeper in the NL Central cellar if not for Travis Wood. By throwing more first-pitch strikes and attacking lower in the zone, the left-hander has practically halved his earned run average
Being a fourth-year player who has yet to gain arbitration eligibility makes Wood the most affordable pitcher in the Cubs starting rotation. He's part of the team's future (much like newly extended Anthony Rizzo).
With Matt Garza mending, Chicago may soon have a surplus of starters. If Wood continues to excel behind strikeout artist Jeff Samardzija, the front office can dangle its impending free agents for potential contenders to trade for. Flipping them for prospects is a way to accelerate rebuilding.
So Wood will be very important to the Cubs in 2013, either as depth in case they sell off veterans at the trade deadline or as an X-factor if they are to surprise us all and win with their current cast.
Those who doubted Chris Sale's legitimacy coming off an All-Star campaign need only analyze his past five starts (including Sunday night's one-hit shutout). In that span, he has allowed 21 total hits and pitched the Chicago White Sox to victories despite not-so-great run support.
His presence atop the rotation is more vital than ever with Gavin Floyd lost for the season (torn flexor muscle) and John Danks far from trustworthy as he nears his 2013 debut.
Brandon Phillips certainly isn't the best player on the Cincinnati Reds. That distinction belongs to either Johnny Cueto or Joey Votto, with Aroldis Chapman and Mat Latos close behind.
He represents the team on this list, however, because Cesar Izturis and his .156/.270/.156 batting line is the next-best second baseman on the roster.
Beyond his dominance in clutch situations, Phillips infuses flare into his fielding and enthusiasm into the clubhouse.
Nothing beats an elite offensive catcher.
Granted, the Cleveland Indians also get ample production from first baseman/designated hitter Mark Reynolds and several outfielders. But Carlos Santana was behind the plate for most of Justin Masterson's stellar 2011 season, and he's familiar with most of Cleveland's relievers.
Plus, Santana's plate discipline exhausts opposing pitchers (4.38 P/PA).
Through the years, the Colorado Rockies have consistently fared poorly during Troy Tulowitzki's injury-related absences. It's no coincidence that they're overachieving in 2013 with him available.
Todd Helton has the longest tenure with the team, but Tulo is gifted with a broader skill set.
Durable rotation leaders like Justin Verlander make life much less stressful for every other pitcher on the staff.
His efficiency and tolerance for high pitch counts ensure that few (if any) relievers will be called upon. Losing streaks rarely extend following his outings, so the other starters don't find themselves under pressure to halt a significant skid.
Even the sabermetrics that consider him baseball's best pitcher can't fully grasp how indispensable he is to the Detroit Tigers.
There's absolutely nobody else worth watching on the Houston Astros.
Jose Altuve, 23, ignites the offense and will be asked to do so throughout this arduous rebuilding process. His small stature generates curiosity among the fans, yet as a middle infielder, it doesn't hinder his fielding performance.
Arguments could be made that fellow rotation members James Shields and Ervin Santana have performed just as well as Jeremy Guthrie in 2013.
On his way to a 5-0 record and 2.28 earned run average, however, Guthrie has put on a clinic about staying composed with runners in scoring position. Opposing lineups own an anemic .188/.188/.188 batting line against him in such situations.
Also, unlike those other veterans, he willingly chose to stay with the Kansas City Royals this past winter (re-signed as free agent). His success brings a lot of credibility to the front office and could entice other available players to come to K.C. in the future.
Weaver suffered an elbow fracture in his second start of 2013.
Less than half of all outings by Los Angeles Angels starters have met the modest requirements for a "quality start" (3 ER in 6.0 IP). Jered Weaver, by comparison, provides that decency more than two-thirds of the time.
The three-time All-Star has mastered the art of inducing soft fly balls. Even with reduced velocity, Weaver will be treated as a savior upon activation from the disabled list.
Less than two months after all those "What will the Los Angeles Dodgers do with their surplus starting pitchers?" conversations, the team is asking its farm system for innings. Other weaknesses like Brandon League would be further exploited if Clayton Kershaw didn't go the distance every few turns of the rotation.
At only 25 years old, he's established as one of the sport's very best left-handers.
Ricky Nolasco doesn't want to be with the Miami Marlins (h/t ESPN), and Kevin Slowey's implosion against the powerless Los Angeles Dodgers might indicate the beginning of his regression.
Jose Fernandez is much more dynamic than either of them, anyway.
With Giancarlo Stanton far from healthy and rumored to be on the trading block—though the team denies it (h/t MLB Network's Peter Gammons)—the Fish care more about the success of this long-term building block.
Jean Segura has been among the most valuable major league players of 2013.
Though Ryan Braun is also in that stratosphere, his younger understudies would be reasonably productive if given regular usage in his absence. Without Segura, 36-year-old Alex Gonzalez and his .193/.227/.253 batting line would be forced into action.
Joe Mauer's strikeout rate is a bit alarming, but whenever he makes contact, the ball finds a gap in the defense. As always, the franchise cornerstone expresses humility in victory.
At this rate, Mauer will catch nearly as many innings as he has the past two seasons combined.
The "veterans" in the New York Mets rotation have been wholly disappointing. Johan Santana, of course, underwent season-ending surgery already, while Shaun Marcum (8.59 ERA) has performed worse than anybody expected.
Second-year phenom Matt Harvey is sparing this team the indignity of falling behind the Miami Marlins. He consistently limits baserunners, spells the bullpen with lengthy outings and excites the fans with his sensational stuff.
He's indispensable from both a competitive and marketing standpoint.
We're all very aware that the New York Yankees have noteworthy individuals on the disabled list. Curtis Granderson and Mark Teixeira, both of whom perennially contribute big power numbers, have combined to take zero meaningful swings in 2013. Though Alex Rodriguez and Kevin Youkilis are on the decline, their past production speaks for itself.
In their absences, Robinson Cano has led New York's rise to the top of the AL East. His .311/.354/.581 batting line entering May 13 makes the high-profile absences far less noticeable.
Moreover, he's doing it as a second baseman. The Yankees don't have any trade targets or internal options with comparable abilities.
Since Coco Crisp's hamstring injury, the Oakland Athletics have derailed. It has been challenging for this lineup to produce without a true speedster.
Crisp aids the A's in manufacturing runs with his smooth swing and aggressive baserunning. He contributes in the field with above-average range in center.
Also keep in mind that the 33-year-old is the only one of Oakland's position players to experience a World Series championship. Crisp knows what it takes to get there.
The Philadelphia Phillies already face sizable deficits in the division race and NL wild-card standings. They fortunately do not have late-inning concerns like the Arizona Diamondbacks and Washington Nationals.
Philly's overeager lineup and mediocre defense won't contribute to many convincing wins. The organization will lean heavily on the highly paid right arm of Jonathan Papelbon to close out nail-biters.
The Pittsburgh Pirates still have concerns about the back end of their starting rotation, which is why A.J. Burnett has been so indispensable. The veteran right-hander gives them an opportunity to win whenever he takes the mound.
Aided by gaudy strikeout numbers, Burnett has limited the opposition to three runs or fewer in each of his eight starts. Regularly surviving five-plus innings also testifies to his consistency.
Moreover, the 37-year-old is influential in the clubhouse. He contributes a great sense of humor and oodles of experience as the Pirates player with the most major league service time.
If the front office didn't already appreciate Burnett, it surely began to this past spring. In a ringing endorsement, writes Rob Biertempfel of the Pittsburgh Tribune-Review, he wouldn't want to pitch "anywhere else but Pittsburgh" upon reaching free agency next offseason.
Chase Headley has played all but two innings for the San Diego Padres since returning from the disabled list. There's no other way for the team to compete.
The current starting rotation is inconsistent, and reinforcements like Cory Luebke have undergone major surgery.
The offense—and more specifically, Headley—must excel in 2013.
Just like during his NL MVP campaign, Buster Posey leads the San Francisco Giants in on-base percentage, extra-base hits and OPS.
He has dual importance to the pitching staff as a source of run support and a trustworthy receiver.
Run scoring continues to be a concern for the Seattle Mariners despite all the effort they spent tweaking their roster over the winter.
Felix Hernandez, luckily, doesn't need much of a cushion.
The results have been practically as encouraging for Hisashi Iwakuma (1.74 ERA and 0.74 WHIP), but King Felix is more likely to sustain this level of performance. His .273 BABIP isn't far off his career average.
Pitchers with 30-plus starts in seven straight seasons don't come along often.
The St. Louis Cardinals have gaudy pitching stats, so the hurlers themselves deserve ample credit for staying well-conditioned and executing.
But Yadier Molina largely influences those results, too. He takes the time to get acclimated with his battery mates so that they are comfortable with his decisions on game day.
On top of that, the 30-year-old is a .343/.376/.463 batter who seldom strikes out.
On a roster that's loaded with versatility, the Tampa Bay Rays have others capable of handling the responsibilities of a third baseman.
However, they wouldn't stay in the playoff hunt without Evan Longoria. Just look at how the 2012 season unfolded.
Even though James Loney has been outstanding, there's no debate who possesses greater power and defensive prowess.
An elite strikeout pitcher is invaluable for the Texas Ranges. Once the weather warms, seemingly innocuous swings can do a lot of damage if they make contact.
Since the latter portion of 2012, Yu Darvish has focused on developing a consistent release point to disguise his pitches.
The right-hander is performing at an even higher level this season. His .163 batting average against—and this gif—attest to that.
Closer Casey Janssen is the lone Toronto Blue Jays player having a notable year thus far. With that said, he shouldn't be pressured to salvage their 2013 season.
Despite a shorter tenure with the team, Jose Bautista has more of a leadership role. Demonstrating his usual power and patience would be worth a handful of wins above replacement.
The otherwise free-swinging offense that has sputtered with him would be impotent without him.
Each member of the Washington Nationals starting rotation has great potential, but Jordan Zimmermann is by far the safest bet among the five.
Manager Davey Johnson could lose the rest of his hair from watching Gio Gonzalez doom himself with wildness. Ross Detwiler lives and dies with the fastball, Dan Haren can't get away with mistakes anymore, and Stephen Strasburg still struggles to control his emotions.
Zimmermann leads the group in most significant categories, and it wouldn't be surprising if that was still true at season's end.