The Padres also announced that the remainder of manager Bud Black's coaching staff will return, including bench coach Dave Roberts, pitching coach Darren Balsley, third-base coach Glenn Hoffman, first-base coach Jose Valentin, bullpen coach Willie Blair and assistant hitting coach Alonzo Powell.
The team said that Powell will be among several candidates to interview for the hitting-coach position.
As for Plantier, it's unclear what his next move might be, though there could be an opportunity for him to remain with the organization in a different role.
The Padres ranked 30th in the Majors in runs (535), hits (1,199), RBIs (500), batting average (.226), on-base percentage (.292) and slugging percentage (.342).
In June, the Padres hit just .171 -- the lowest single-month mark by a team in the modern era (or since at least 1914). It was also in June when the team was no-hit by Tim Lincecum of the Giants, one of 19 shutouts the team would incur in 2014.
Yonder Alonso, Will Venable, Carlos Quentin, Chase Headley (traded in July to the Yankees), Cameron Maybin, Everth Cabrera, Jedd Gyorko and the first five months for Yasmani Grandal -- players the team was heavily depending on -- all finished below where they had been before in batting average and, for many, below in terms of overall offensive production.
"Anytime you have the pitching we did, there is no reason why we shouldn't have been better than we were," Gyorko said in September. "All we needed, on most days, was three or four runs a game. That's all. But when you dig yourself a hole like we did, it's tough to climb out."
The other Padres hitting coaches since the team moved to spacious Petco Park were Dave Magadan, Merv Rettenmund, Wally Joyner, Jim Lefebvre and Randy Ready.
All of those coaches, with the exception of Magadan, worked under Black since 2007.