But along with wanting to stick with the hot hand at the top of his lineup, the manager's decision was also influenced by the fact Evan Gattis is expected to fill the cleanup spot on a regular basis while Freddie Freeman spends the next two weeks on the disabled list with a strained right oblique muscle.
Gattis made his second straight start at catcher on Monday, and he is expected to get more playing time than Gerald Laird over the next couple of weeks.
"I did a couple lineups and it just seems right when you put B.J. there, especially now that Freeman is not in the middle of the lineup," Gonzalez said. "If you lead Simmons off, the bottom third of that lineup gets clogged up a little bit. Then you've got to either hit Chris Johnson or [Juan] Francisco [eighth]."
Gonzalez moved Simmons to the eighth spot with the hope that his ability to consistently put the ball in play would help turn the lineup over.
"I like hitting leadoff," Simmons said. "But it's not an issue."
Simmons said that his thumb, which he hurt sliding into second base on Friday night, also will not be an issue. He will wear a wrap on his hand to keep the thumb stable until it completely heals.
Upton has hit .249 with a .331 on-base percentage in 167 career games in the leadoff spot. After going hitless in his first 16 at-bats of this season, he entered Monday having reached safely with a hit or a walk in five of his last six plate appearances.
While there was some discussion about entering the season with Upton in the leadoff spot, Simmons was essentially given the role by default. The slick-fielding shortstop hit .289 with a .335 on-base percentage while compiling just 182 plate appearances after making his Major League debut last year.
"It's fine," Simmons said. "Whatever works. If we keep winning, that's fine with me."
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.