Keys to success? Unlocking each team's integral component

Who is your team's most important player in 2015? Not its best player. Not its highest-paid player. Just the guy whose performance might guarantee a successful season. Every club has a player -- or perhaps two -- like that.

Let's call it "30 players, 30 teams." Right about now, every general manager is playing some version of this game. That is, they look at their roster and see things of which they're absolutely certain. For instance, the Red Sox believe they can write down David Ortiz's 2015 statistics and be within an eyelash of where the real numbers end up.

And then there are things teams believe with some level of confidence will happen. These range from young players getting a chance to play to players coming back from injuries. There are also players a general manager looks at and thinks, "If this guy is great, we're in good shape."

Here's my list:

American League East

Blue Jays: Brett Cecil
If he can handle the closer's role -- and he has a 2.76 ERA over 126 appearances the last two seasons -- Toronto could slide Aaron Sanchez and his 97-mph fastball into the rotation.

Orioles: Chris Davis
The O's have less margin for error after losing Nelson Cruz and Nick Markakis in free agency. They need Davis to be close to the guy he was in 2013, when he led the AL with 53 home runs and 138 RBIs.

Rays: Evan Longoria
Tampa Bay is, as usual, counting on a bunch of young guys -- Steven Souza, Kevin Kiermaier, Brandon Guyer, perhaps Tim Beckham. Longoria getting back to his 2013 numbers (39 doubles, 32 home runs, 70 walks) would go a long way toward taking some of the pressure off them.

Red Sox: Clay Buchholz.
Boston has the makings of a very good, very deep rotation. The Red Sox are not relying on Buchholz the way they once did. But he could elevate this team in a big way.

Video: Sabathia confident he can bounce back in 2015

Yankees: CC Sabathia
The burly left-hander's days of being a No. 1 starter probably are over. But if he can just stay healthy, Sabathia surely can still give the Yanks the quality innings they badly need.

AL Central

Indians: Trevor Bauer
Bauer showed flashes last season of fulfilling those huge expectations, and he could help deliver a division championship to the Tribe in 2015.

Royals: Mike Moustakas
He's 26 years old and has 1,830 big league at-bats and one very sweet postseason under his belt. If Moose takes another step forward, it would go a long way toward giving Kansas City a lineup capable of a second straight playoff run.

Video: DET@KC: Verlander tosses 7 1/3 of one-run ball

Tigers: Justin Verlander
Despite the changes, Detroit could still have a first-rate rotation. But the Tigers need a healthy -- and productive -- Verlander.

Twins: Byron Buxton
A potentially franchise-changing player. No time like the present.

White Sox: Avisail Garcia
The White Sox probably can win the AL Central without Garcia being great. But his upside is so high, he could transform an already solid lineup into one of baseball's best.

AL West

Angels: C.J. Wilson
The veteran left-hander is so smart and so competitive that it would be a huge mistake to discount him. If there's gap between the Mariners and Halos, Wilson surely could close it.

Astros: Jon Singleton
He passed every test in the Minors, but his first big league season was a huge struggle. For a team that badly needs more offense, Singleton could provide it.

Athletics: Marcus Semien
He was one of the keys of GM Billy Beane's roster renovation. If Semien can be a productive everyday shortstop, he'd go a long way toward helping the A's to a fourth straight postseason appearance.

Video: SEA@HOU: Walker fans seven over 5 1/3 innings for win

Mariners: Taijuan Walker
The young right-hander has the ability to transform a good rotation to a great one. Still only 22 years old, his time has come.

Rangers: Prince Fielder
The veteran slugger is the difference between an average offense and a potentially very good one. He's also possibly the difference between making and missing the playoffs.

National League East

Braves: B.J. Upton
If Upton can resurrect his career, he could give Atlanta another important piece -- either as a trade asset or an impact player.

Marlins: Jose Fernandez
Even if he doesn't return until August, Fernandez could be a difference-maker down the stretch.

Video: Outlook: Fernandez could make second-half impact

Mets: Matt Reynolds
Is this where the never-ending search for a shortstop ends? Reynolds has passed every test in the Minors. Why not?

Nationals: Drew Storen
Closer is pretty much the only area where the Nats have a question mark. Storen will get first crack at the job. If he struggles, Casey Janssen is waiting in the wings.

Phillies: Ryan Howard
This is about an exit strategy for a player with $60 million remaining on his contract. If he can show other teams he still has value, Howard could perhaps put a nice touch on a great career and get GM Ruben Amaro Jr. another piece for his roster reconstruction.

NL Central

Brewers: Ryan Braun
The first rule of contending is that stars have to play like stars. With Milwaukee, that begins with the right fielder.

Cardinals: Jason Heyward
The outfielder will impact his new team, both offensively and defensively. This appears to be the start of a beautiful marriage.

Cubs: Kris Bryant
Pick a name. The Cubs are going to have so many talented young guys, it's impossible to know where to begin. Bryant is at the top of this list.

Pirates: Gregory Polanco
If the young outfielder is what he has been projected to be, the Bucs potentially could have baseball's best offense and be on their way to a third straight postseason appearance.

Reds: Homer Bailey
There's less margin for error in the rotation. Bailey may not be ready for Opening Day, but his recovery from a right forearm injury is huge for a team that appears good enough to contend.

NL West

D-backs: Mark Trumbo
If the slugger is healthy and productive, he could settle into the middle of the order with Paul Goldschmidt and Yasmany Tomas to give Arizona the makings of a nice offense.

Video: Outlook: Trumbo possesses elite power, low average

Dodgers: Jimmy Rollins
The veteran shortstop is about to show the world he's still capable of greatness.

Giants: Angel Pagan
San Francisco was 57-39 when Pagan played last season, and with Pablo Sandoval gone, his offense is needed more than ever.

Padres: Josh Johnson
Johnson has the stuff of a No. 1 starter. If he can stay healthy, he would be one of the smartest pickups GM A.J. Preller made.

Rockies: Eddie Butler
On a team desperate for pitching, the solid prospect will get a chance.