New York Yankees' fans are familiar with the phrase 'Core Four.' That represents the group of four players -- Mariano Rivera, Derek Jeter, Andy Pettitte and Jorge Posada -- who came through the farm system together and were instrumental in five World Series titles during their playing careers.

Well, MLB.com has taken the 'Core Four' concept a step further. MLB.com is asking fans of every major league to vote on the 'Franchise Four' for their team -- the four best players in franchise history.


You can, of course, skip straight to the Yankee poll.

Voting, incidentally, ends on May 8. The 'Franchise Four' results will be announced July 14 at the All-Star Game in Cincinnati.

So, who would be in your 'Franchise Four' for the Yankees?

The MLB.com poll offers the following choices:

Yogi Berra, Joe DiMaggio, Whitey Ford, Lou Gerhig, Mickey Mantle, Babe Ruth, Derek Jeter, Mariano Rivera.

Choosing four isn't as easy as you might think. Or, shall I say, choosing the fourth member of the 'Franchise Four' isn't as easy as you might think. At least not for me.

I would be surprised if anyone wants to argue with the assertion that are three no-brainers on the list. Ruth is a lock, the game's first great home run hitter, maybe still its best, and without doubt its first over-sized personality. Gehrig and Dimaggio, as well.

Where it gets interesting is the fourth choice. 

There is Berra, the best catcher in franchise history. A three-time MVP and 15-time All-Star. A member of the Baseball Hall of Fame, of course.

The Yankees won 10 World Series titles with Berra on their roster.

There is Ford, the best starting pitcher in franchise history. Won 236 games over 16 seasons and pitched in 11 different World Series, helping the Yankees win six titles. Went 25-4 and won the Cy Young Award in 1961. An eight-time All-Star and Hall of Famer.

There is Jeter, the just-retired best shortstop in franchise history. Had 3,465 hits in a 20-year career, making the All-Star Team 14 times. Was 1996 Rookie of the Year. Won five Gold Glove Awards. Won the Silver Slugger Award as the league's best-hitting shortstop five times. The Yankees won five World Series titles with him at shortstop. Will be a first-ballot Hall of Fame selection.

There is Mantle, probably the most naturally-gifted player to ever wear Yankee pinstripes. Hit 536 career home runs. Made the All-Star Team 16 times in 18 seasons. Won the MVP Award three times. Played on seven World Series winners. Is, of course, a Hall of Famer. Imagine the numbers Mantle would have produced with good knees and a healthier lifestyle.

There is Rivera, the best relief pitcher baseball has ever seen. Holds the major league saves record with 652, and the record for most games finished (952). Pitched to a career ERA of 2.21 over 19 seasons and 1,115 appearances. Had an incredible 0.70 ERA with 42 saves in 96 postseason games covering 16 seasons with postseason appearances. Made the All-Star Team 13 times. Was part of five World Series-winning teams, closing for four of those.

Who is my choice?

Rivera. No relief pitcher has ever approached Rivera's level of excellence, or done it as brilliantly as he did for such an extended period of time. Most relief pitchers, even the best, have a handful of outstanding years and then flame out. Not Rivera. He was unhittable as a 25-year-old rookie, and was still unhittable as a 43-year-old coming back from a torn ACL. From 1997 to 2013 the Yankees' plan was simple, and feared by everyone they played against. Get the ball to Mo.

Which four players would you choose, Yankees fans? Don't miss your chance to vote.

[NOTE: Statistics from Baseball-Reference.com.]