There may not be a nicer man in baseball than Adam Warren. But though he was respected by the Yankees' hierarchy, he always seemed to be an afterthought in the team's plans. The topper came at the end of June last season, when he was lifted from the starting rotation, even though his ERA was 3.59, while CC Sabathia's was 5.65.

There was neither a public complaint or a peep from Warren. He just went to the bullpen, did his job and the Yankees finally restored him back to the rotation in the middle of September.

Of all the Yankees who started 17 or more games, Warren's 3.66 ERA only trailed Masahiro Tanaka's 3.51. (Luis Severino had a 2.89 ERA in 11 starts.) His success led to the Yankees filling their biggest offseason need, as they traded him to the Chicago Cubs to acquire a starting second baseman in Starlin Castro.

Warren, 28, is the kind of guy you may not appreciate fully until he is gone. In 162 games, a solid swing man, with no whine in him, is in the words of Yankees GM Brian Cashman, a "tremendous asset."

"He always did everything he was asked," Cashman said. "That's how he is wired."

The Yankees' starting staff is filled with more questions than a philosophy major. Tanaka, Nathan Eovaldi and Ivan Nova all are dealing with elbow issues, while Sabathia is returning from alcohol rehab and a bad knee. Michael Pineda always seems like an injury waiting to happen, while Severino, who impressed in his first taste of the bigs in 2015, will be starting his first full season.

Cashman declined to say which pitchers are already guaranteed spots in the rotation, but -- in the unlikely event there are no injuries during the spring -- Sabathia and Nova are probably the ones fighting for No. 5.

Sabathia is owed $25 million in 2016 and only needs to keep his shoulder healthy to pocket another $25 million in 2017, while Nova is entering a free-agent year. They're both good guys, but neither will want to be the sixth starter, if it comes to that.

While Cashman wouldn't guarantee anyone a starting spot, we will.

If healthy, Tanaka, Severino, Pineda and Eovaldi will be in the rotation, leaving the last spot for either Sabathia or Nova. Sabathia will have the inside edge, given his pedigree, his use of his left arm to throw and the big check that arrives each pay day.

"Hopefully, it is a decision made by us and not injury," Cashman said.

There will be injuries during the season, making it important for the Yankees to have starting depth. After the big six, Bryan Mitchell, Luis Cessa and Chad Green are next up on the depth chart, though that number will expand with non-roster invitees to spring training.

Mitchell was up and down last year, while Cessa and Green -- acquired in the Justin Wilson deal with Detroit -- have yet to pitch in the majors. Can any of them be a glue guy, like Warren?

Warren helped keep the Yankees together through the long haul last season. He pitched 131-1/3 innings, going 7-7 with a 3.29 ERA in 17 starts and 26 relief appearances.

His performance is not something many fans will remember in 20 years, but he was dependable, on and off the field. The Yankees don't have an obvious choice to replace Warren -- a guy who accepted his role and had the ability to perform in it.

It isn't the biggest question facing the 2016 Yankees, but when you talk about the difference in making it to October and going home early, having the next Adam Warren is important. Especially for a team that doesn't have much room for error.