After getting three consecutive playoff berths from 2013 to 2015, the Pirates have finished below .500 in back-to-back seasons. With limited resources to make major offseason additions, they’re more likely to be sellers, with outfielder Andrew McCutchen and No. 1 starter Gerrit Cole the most valuable trade chips. USA TODAY’s Steve Gardner takes an in-depth look at the team. (*prospect)

Catcher

In the second year of a three-year extension, Francisco Cervelli is the Pirates’ second-highest-paid player. However, he was limited to 81 games last season, going on the disabled list twice because of concussions, wrist and leg injuries. He is very good defensively but doesn’t contribute much on offense. Backup Chris Stewart wasn’t re-signed, leaving the team with little experience behind the plate if Cervelli can’t stay healthy.

Depth chart: Cervelli, Elias Diaz, Jacob Stallings

MORE MLB NEWS

First base

Josh Bell, 25, made the conversion from the outfield to a full-time first baseman as a rookieand finished with positive defensive value (+6 Defensive Runs Saved). He led the team in RBI and answered questions about his power potential by finishing second on the team to McCutchen in homers. Jose Osuna, also 25, got his first taste of the majors last season at first base and in the outfield. Fan favorite Sean Rodriguez was reacquired in a midseason trade and can fill in anywhere except pitcher and catcher.

Depth chart: Bell, Osuna, David Freese, Rodriguez

Second base

The Pirates have fielded inquiries this offseason about veteran Josh Harrison, who posted career highs in home runs and slugging percentage. However, Harrison broke his hand in September and might not be ready for the start of spring training. Adam Frazier was a pleasant surprise in 2017, filling in at second base and the outfield and serving as the team’s leadoff man. Switch-hitter Max Moroff, 24, showed excellent on-base skills in the minors but struggled in his first extended time in the majors.

Depth chart: Harrison, Frazier, Rodriguez, Moroff, Chris Bostick

Shortstop

Once again, Jordy Mercer provided steady production and solid defense as the everyday shortstop. He’s eligible for arbitration for the last time this season before he becomes a free agent. Moroff could be a stopgap replacement until former first-round picks Kevin Newman (2015) and Cole Tucker (2014) are ready for the majors. The Pirates also picked up defensive whiz Engelb Vielma on waivers to compete for a utility spot.

Depth chart: Mercer, Moroff, Rodriguez, Vielma, *Newman, *Tucker

Third base

With Jung Ho Kang unable to get a work visa because of a drunken-driving arrest in his native South Korea, third base is one of the Pirates’ most pressing needs. Freese played 116 games there, but he turns 35 in April. Osuna might be a possibility after getting reps at the hot corner in the Venezuelan Winter League, but it’s hard to see him as an everyday player there with so little experience.

Depth chart: Freese, Rodriguez, Frazier, Osuna, Moroff, Vielma, *Ke’Bryan Hayes

Left field

When everyone’s healthy, the Pirates have one of the best outfields in the game. Starling Marte began last season in center field, but his 80-game suspension in April for a positive drug test shifted McCutchen back to center. Besides the missed time, Marte posted career lows in batting average, on-base percentage and slugging. Expect those numbers to bounce back. Frazier spent the majority of his time in left with Marte out but figures to see more action in the infield. Jordan Luplow played 44 games at the Class AAA level before getting the call to the majors. He might need more minor league seasoning, so the Pirates will look to add outfield depth before spring training opens.

Depth chart: Marte, Frazier, Luplow, Osuna, Rodriguez

Center field

After critics said he’d lost a step, McCutchen improved his offensive numbers across the board and was much better on defense than his dismal 2016 metrics suggested. He’ll be a free agent at the end of next season, his 10th with the Pirates. Trade rumors surrounded him at this time last year, too, and nothing happened. But if McCutchen is dealt, it will be because the front office thinks top hitting prospect Austin Meadows is ready to play every day. Meadows battled injuries last season and hit .250 and four home runs in 284 at-bats at Class AAA Indianapolis.

Depth chart: McCutchen, Marte, Frazier, Rodriguez, *Meadows

Right field

Gregory Polanco battled hamstring issues all season, going on the disabled list three times. As a result, he took a significant step backward from a 22-homer, 17-steal season in 2016. On a positive note, Polanco lowered his strikeout rate below 15%, he can play all three outfield positions and he’s only 26.

Depth chart: Polanco, Luplow, Frazier, Osuna, *Meadows

Rotation

The Pirates pitching staff ranked 13th in the major leagues last season with a 4.22 ERA, and Pittsburgh will bring back all five members of its starting rotation, each of whom made at least 25 starts. However, Cole, 27, has been a topic of conversation for teams looking to upgrade their rotations. The right-hander tied for the National League lead with 33 starts and has two years of team control remaining. Cole and Jameson Taillon, 25, are the only two starters who could be considered power pitchers. The other members of the all-righty rotation tend to rely more on finesse and location. The organization’s top overall prospect, 21-year-old right-hander Mitch Keller, was impressive in the Arizona Fall League and could be considered for a call-up in September.

Depth chart: RHP Cole, RHP Taillon, RHP Ivan Nova, RHP Chad Kuhl, RHP Trevor Williams, LHP Steven Brault, *RHP Tyler Glasnow, RHP Nick Kingham, *RHP Keller

Bullpen

Hard-throwing left-hander Felipe Rivero was one of the game’s best closers after taking over the role in June. He converted 21 of 23 save chances and struck out an impressive 10.5 batters per nine innings. The rest of the bullpen is largely unproven, though the Pirates could use Glasnow, 24, and Brault, 25, for multiple innings. Both project as starters long term but will begin the season in relief.

Depth chart: LHP Rivero, RHP Daniel Hudson, RHP George Kontos, RHP Glasnow, LHP Brault, RHP A.J. Schugel, RHP Dovydas Neverauskas, LHP Nik Turley, RHP Edgar Santana, RHP Johnny Barbato

Top 5 prospects

Excerpted from BaseballHQ.com’s 2018 Minor League Baseball Analyst. To order: http://www.baseballhq.com/minor-league-baseball-analyst

1. Mitch Keller, RHP: Keller has the best stuff in the system, but he continues to battle injuries. His mid-90s fastball has late sink, while an improved changeup, above-average curveball and solid command give him front-line tools. The 21-year-old has a career 9.5 strikeouts/nine innings and 2.79 ERA. He’ll return to Class AA.

2. Austin Meadows, OF: It was another lost season for highly touted Meadows, as injuries limited him to 81 games. He hit .250 in Class AAA and four home runs, but his five tools remain intact and he’s still 22. Meadows will likely return to Class AAA.

3. Shane Baz, RHP: The 12th overall pick of the 2017 draft, Baz is a physically mature high schooler. His fastball sits in the mid-90s with good sink, and he backs it with a cutter and plus slider. Just 18, Baz should head to short-season ball.

4. Ke’Bryan Hayes, 3B: Hayes hit .278 with 27 stolen bases at high Class A after breaking his rib early in the season. He has a professional plate approach and should continue to hit as he moves up. At 20, Hayes was one of the youngest players at his level, so the power should develop once he learns to turn on pitches.

5. Cole Tucker, SS: Tucker had his best year as a professional (.275 batting average, 47 stolen bases) between high Class A and AA. He is a plus runner who should stick at shortstop and could grow into average power once his 6-3 frame fills out. His pitch recognition and on-base ability allow the speed to play up.

-- Rob Gordon

Gallery: Top 2017-18 free agents