Each Friday leading up to Spring Training, MLB.com will be taking a look at a different position as part of the Pirates' 2013 season preview. This week, the starting rotation. Next: We'll wrap up with the bullpen.

When the Pirates hosted the Reds in the penultimate series of the 2012 season, it was with more than a little measure of awe and envy that manager Clint Hurdle surveyed the rotation of the newly crowned National League Central champs.

"They've got four guys who've thrown 200 innings," Hurdle noted. "To me, that's an incredible achievement."

A modern-day perspective, to be sure -- 200-inning pitchers were common not too long ago, and we even had a 300-inning guy as recently as 1980 (Steve Carlton) -- but even by that relative yardstick, Hurdle's Bucs were falling short.

A.J. Burnett (202) was the only one to exceed 171 innings, but Hurdle was more dismayed by the collective workload. Entering the season, he and pitching coach Ray Searage had stressed that pitching deeper into games -- and thus keeping relievers fresher -- was critical to the Pirates' improvement.

Despite that emphasis, Pittsburgh starters in 2012 worked about the same number of innings (934 2/3) as they had in 2011 (923 1/3). Sure enough, the toll on relievers again contributed to another fade: They suffered 13 losses and had a 4.15 ERA in the second half, compared with going 14-6 with a 2.63 ERA prior to the All-Star break.

Will the 2013 rotation be able to handle a bigger load? That objective remains the same, but the arms have changed. The Bucs had a measure of certainty a year ago, as they approached the season with six veteran, established starters. Of them, Erik Bedard and Kevin Correia are gone, and Charlie Morton is on the long road of recovery from Tommy John surgery.

The new face out of the gate will be Wandy Rodriguez, and the Bucs are very encouraged by what he brings to the top of the rotation. The lefty was by far the team's best in the last month of the season, once he adjusted to his late-July trade from Houston, and having him from the opening bell improves the Pirates' shot at an important fast getaway.

Rodriguez knows all about hot starts, with a career first-month ERA of 2.95, including 1.72 with the Astros last season. He has averaged 197 innings the last four seasons, and he actually worked a career-most 205 2/3 in 2012 -- albeit only the last 75 of that was on the Pirates' behalf.

Rodriguez hooks up with Burnett to give Hurdle what he calls the best 1-2 he has ever managed. Perhaps mild praise, given that all of Hurdle's prior managerial experience had come in the pitching-unfriendly environs of Denver. But there is no question Burnett fulfilled every definition of "ace" in his first season with the Pirates.

Normally, there has to be some concern when your No. 1 turns 36 -- as did Burnett in January. However, coming to Pittsburgh was so rejuvenating for the righty, his "pitching age" doesn't match the birth certificate.

James McDonald's role remains unchanged: He can still be considered the difference-maker, as he was a year ago. Indeed, he had the Bucs soaring with his first-half work, before his puzzling and frustrating personal U-turn.

Into the All-Star break, J-Mac had a 2.37 ERA and was holding batters to a .196 average. He came out of it with a 7.52 ERA and .292 opponents' average. It was a total breakdown, and his recovery holds a big key.

If McDonald can stay effective and Jeff Karstens can stay healthy, the Bucs could have the Big Four to rival that of Cincinnati. When he's been on the mound without shoulder or leg concerns, Karstens has been top notch the last two seasons. The bad news is that he was able to work only 253 innings during that time.

Thereafter, the picture gets a little hazy. Two veteran arms are in the hole, Morton's quite a bit deeper. The Pirates hope to have him throwing off a mound before Spring Training ends, but he is not likely to be available until July at the earliest. Then there is the mystery man, left-hander Francisco Liriano, who six weeks after reaching agreement on his original two-year contract has still not officially surfaced as a member of the Bucs.

By this point, it must be assumed his prerequisite physical won't be administered until he gets to Pirate City. Then, finally, there might be some clarification of how long the broken right arm will defer his participation.

If Liriano cannot hook into the season-opening rotation, there will be many candidates for the spot, leading with lefty Jeff Locke and Kyle McPherson, both of whom are certain to contribute at some point of the long season.

Same goes for Gerrit Cole, No. 9 on MLB.com's list of Top 100 Prospects, who is most likely to open the season in Triple-A Indianapolis.

Others getting consideration will include a trio of lefties: Kris Johnson, the Minor League veteran who turned heads while splitting last season between Double-A Altoona and Indianapolis and continued turning them in the Dominican Winter League; Andy Oliver, a former up-and-comer with the Tigers; and Justin Wilson, who was very sharp in a September audition out of the bullpen but is a starter by trade. Add to the mix Jeanmar Gomez, who made 38 starts for the Indians in 2010-12, and perhaps even Chris Leroux, who has been a reliever most of his professional career but successfully transitioned to part-time starter last season in Indianapolis.