With Spring Training approaching, it's time for an in-depth look at the Pirates' roster. This is the seventh part of a series checking in on their current and future options at each position. Next up: the starting rotation.
Big question: Will the starters' production match their potential?
Ivan Nova, the rotation's elder statesman at all of 31 years old, has made 160 starts in the Majors. The next six pitchers on the Pirates' depth chart have combined to start 167 games. Pittsburgh's starting staff doesn't have a long track record, but it's a deep group full of potential.
They've shown their ability -- Jameson Taillon before his testicular cancer diagnosis, Chad Kuhl in the second half last year, Joe Musgrove as a starter (2016) and reliever ('17), Trevor Williams after joining the rotation, Steven Brault last September and Tyler Glasnow in the Minors. But only one has put it all together consistently enough to post an MLB ERA and FIP below 4.00: Taillon (3.98 ERA, 3.58 FIP).
Around the Horn:Catcher | First base | Second base | Third base | Shortstop | Outfield
Without Gerrit Cole, the young starters must take steps forward. Will they do it this year?
The likely starters: Taillon, Nova, Kuhl, Williams and Musgrove
Odds are those five will break camp in the rotation, though Brault, Glasnow and Nick Kingham will compete for a spot in Spring Training. There's no doubt about Nova and Taillon, and general manager Neal Huntington said earlier this winter they want to respect what Kuhl and Williams did last season.
Williams put up a 3.96 ERA in 25 starts, while Kuhl recovered from a rough first three months by posting a 3.38 ERA in his final 16 outings. Trading Cole left one spot open, but Musgrove is expected to fill it. The 25-year-old pitched better out of Houston's bullpen last season, but the Bucs believe he has what it takes to succeed as a starter.

There is no true staff "ace" without Cole, but it's worth noting he produced a slightly-above-league-average 103 ERA+ the past two years. By comparison, Nova has a 110 ERA+ as a Pirate and Taillon's career mark is 107, even though both significantly slumped in the second half last season. Their challenge is replacing the 203 innings Cole threw without putting a strain on the bullpen.
Depth: Brault, Glasnow, Kingham, Clay Holmes, Tyler Eppler
Williams, considered the No. 6 starter out of camp last year, moved from the bullpen into the rotation in early May. Brault and Glasnow could be on the same track this season due to their Triple-A dominance and the depth behind them.
It's possible one or both could start in Triple-A Indianapolis' rotation, where they would join Kingham, Holmes and Eppler. Kingham and Holmes, both among the Pirates' Top 30 Prospects, are already on Pittsburgh's 40-man roster.

Kingham, 26, posted a 4.13 ERA in 20 Triple-A outings last year. Holmes, a ground-ball machine, put up a 3.36 ERA over a full Triple-A season but struggled with his control (4.7 walks per nine innings).
In the pipeline: Mitch Keller has taken his place as one of the game's best pitching prospects, checking in at No. 16 on MLB Pipeline's Top 100 Prospects list. The 21-year-old righty should begin the season back in Double-A Altoona, which would put a midseason promotion to Triple-A -- and a 2019 debut --within reach.
The Pirates have some more interesting arms entering the upper levels of their system, including right-hander Dario Agrazal (added to the 40-man roster this offseason), hard-throwing lefty Taylor Hearn and southpaw Brandon Waddell. Righty Luis Escobar, who pitched in last year's All-Star Futures Game, should advance to Class A Advanced Bradenton this season after striking out 168 in 131 2/3 innings with Class A West Virginia.

The Bucs have also selected some high-ceiling pitchers in the last two Drafts, including lefty Braeden Ogle and right-handers Travis MacGregor, Steven Jennings and Cody Bolton. But the biggest name in the lower levels is Shane Baz, Pittsburgh's first-rounder last year and MLB Pipeline's No. 67 prospect. Baz is years away from making an impact, but the Pirates love the 18-year-old's arsenal, athleticism and attitude.