MIAMI -- Pitching, speed and defense are three priorities in the Marlins’ building process.

The organization is staying the course in addressing those areas by retaining pitching coach Mel Stottlemyre Jr. and first base/infield coach Trey Hillman.

• Marlins FAQ: How will Miami keep improving?

Both will be part of manager Don Mattingly’s staff in 2020, sources have told MLB.com. The club has not formally announced any coaching decisions, and interviews and evaluations are on-going for several openings.

While Hillman was the first base, infield and baserunning coach this season, there is a chance he will assume another role. From 2011-13, Hillman was Mattingly’s bench coach with the Dodgers. Assuming that position is a possibility.

Tim Wallach, who has been Mattingly’s bench coach the past four seasons, informed the club late in the season that he would not be returning. The 62-year-old is looking to get closer to home in Southern California to be nearer to his family.

Fredi González, the third-base coach the previous three years, expressed to the club earlier this week that he wanted to pursue other options. The 55-year-old also worked with the outfielders. Before his decision to move on, he had been in discussions with the club about returning, perhaps in a different role, like working with the catchers.

All of Mattingly’s 2019 staff were on one-year contracts, which expired at the end of the season. Catching coach Brian Schneider and bullpen coach Dean Treanor also will not be back.

Hillman, 56, will be entering his 30th season as either a Major League coach or manager. Hillman managed the Royals from 2008-10. He also has managed in Japan and Korea.

The 2019 Marlins finished with 94 errors, 17th most in the Majors. Miami also had a Defensive Efficiency Ratio of .710, fourth best in the Majors. The metric, listed on the MLB.com fielding statistics page, rates "defensive outs recorded in defensive opportunities."

Stottlemyre Jr. joined the Marlins in 2019, after spending the previous three seasons as pitching coach with the Mariners. He will have a say in who becomes the next bullpen coach.

Working with mostly a young, inexperienced staff, the Marlins finished 20th in the Majors in ERA (4.74), with their starters ranking 16th at 4.59. An area that the club will stress to improve in is walks. Miami’s starters averaged 3.50 BB/9, 29th in the Majors.

Prior to the All-Star break, the Marlins’ rotation ranked among the best in the Majors. Their 3.92 ERA was seventh overall. But in late July, the rotation and bullpen were impacted by trades. Zac Gallen, a promising rookie right hander, was dealt to the D-backs for shortstop prospect Jazz Chisholm. Right-handers Trevor Richards and Nick Anderson were dealt to the Rays for outfield prospect Jesús Sánchez, and reliever Ryne Stanek.

Reliever Sergio Romo and pitching prospect Chris Vallimont were traded to the Twins for first-base prospect Lewin Díaz.

The rotation in the second half also felt the effects of injuries and wear and tear. José Ureña, the Opening Day starter, missed three months with a herniated disc, and when he returned, it was as a reliever. Pablo López, the No. 3 starter to open the season, missed time with a right shoulder strain, and lefty Caleb Smith, the No. 5 starter at the beginning of the year, was out a month with left hip inflammation.

The attrition played a factor in the Marlins’ starters posting a 5.42 ERA, which ranked 24th in the Majors after the All-Star break.