And for Sunday's series finale against Atlanta (12-30), Mackanin stayed true to his word, giving the 36-year-old Howard the day to himself.
Tommy Joseph will make his first start at first base against a right-handed pitcher, as the Phillies (24-19) seek to salvage a game in their three-game set to the NL-worse Braves.
Joseph, 24, is 4 for 12 with a solo home run in five games since being called up on May 13. It will be his second time batting clean up. He went 3 for 4 with his first career homer the last time he hit fourth, a 3-1 Phillies win May 17 against the Miami Marlins.
Both Howard and Joseph are expected to play during the Phillies' upcoming series in Detroit with the designated hitter in play. The Tigers are scheduled to throw out three righties in the series, so either Howard or Joseph will be at DH and the other at first.
Joseph and the Phillies on Sunday will face Braves right-handed pitcher Casey Kelly, who was called from Triple A Gwinnett after Saturday's game.
Kelly replaced Joel De La Cruz on Atlanta's roster.
Complete coverage of the Fightin' Phils and their MLB rivals from NBC Sports Philadelphia.
In five starts with Gwinnett, Kelly was 2-1 with a 2.63 ERA, striking out 29 batters in 37⅔ innings. Kelly did make one appearance with the Braves earlier this season, allowing one run on three hits in three innings in a 6-3 loss to the New York Mets on April 22.
For the Phillies, Cesar Hernandez returns to the lineup after having Saturday off. The second baseman, who's hitting .261 with eight RBIs, will bat second. With Joseph batting clean up, third baseman Maikel Franco moves up to third in the lineup.
Other changes from Saturday include Cameron Rupp behind the plate, Peter Bourjos back in right field and batting ninth and Freddy Galvis moving from the two hole to sixth.
Jered Eickhoff (1-6, 4.44 ERA) will be on the mound for the Phils. Eickhoff enters the ballgame struggling in his last five starts, going 0-5 with a 5.45 ERA with opponents hitting .293 against him and slugging six homers off the righty.
Eickhoff is 0-1 with a 2.38 ERA in two career starts against Atlanta.
Here are today's full lineups:
1. Odubel Herrera, CF
2. Cesar Hernandez, 2B
3. Maikel Franco, 3B
4. Tommy Joseph, 1B
5. Cameron Rupp, C
6. Freddy Galvis, SS
7. Tyler Goeddel, LF
8. Jered Eickhoff, P
9. Peter Bourjos, RF
1. Ender Inciarte, LF
2. Chase d'Arnaud, 3B
3. Freddie Freeman, 1B
4. Nick Markakis, RF
5. Gordon Beckham, 2B
6. A.J. Pierzynski, C
7. Daniel Castro, SS
8. Casey Kelly, P
9. Mallex Smith, CF