Question 7: Who will be the X factor in '14?

Michael Pineda and Jacoby Ellsbury are big pieces of the Yankees' 2014 puzzle. Getty Images/USA TODAY Sports

As we count down to Opening Day, Wallace Matthews and Andrew Marchand will answer 14 for '14 -- the top 14 questions facing the 2014 New York Yankees. The series will run until the eve of the first pitch between the Yankees and Astros on Tuesday, April 1, and will end with both Matthews and Marchand making their predictions for the season.

Question: Who will be the Yankees' X factor in 2014?

Andrew Marchand: Michael Pineda not only won the fifth starter spot in spring training, but he was also probably the Yankees' most impressive starter. Pineda may not be throwing 97, but he gave the Yankees a chance to dream that he could eventually be a No. 1, 2 or 3 starter.

For this season, he may be the guy to pick up the slack if CC Sabathia and Hiroki Kuroda are just good, not great, starters. If Pineda continues what he did in Tampa, Fla., as he debuts as a regular-season Yankee -- remember he has never thrown a pitch in a real game in pinstripes -- then he could be the difference between a playoff season and another empty October.

Wallace Matthews: I agree Pineda could be a VIY -- Very Important Yankee -- this year, but I'm going with Jacoby Ellsbury, for several reasons.

The most important one is that you can never be sure how many games he will play. Last year, he played 134. The year before that, 74. The year before that, 158. The year before that, 18. You get the picture. And already he has missed most of spring training with an injury he has described as "basically nothing."

But if he's in the lineup on a regular basis, I believe he will transform the Yankees' offense. Think of him as a Brett Gardner with power, especially in lefty-friendly Yankee Stadium, and no reluctance to steal bases. With him at the top of the order and Gardner presumably batting ninth, once the lineup turns over you essentially have two speedy leadoff hitters in a row to contend with. That should translate to a lot of baserunners and, assuming the rest of them do their jobs, a lot of runs.

That should add a dimension to the Yankees' offense that was missing last season. That is, of course, if Ellsbury remains healthy enough to stay on the field. That is the great unknown this season, hence the X.