The speedy Gordon is hitting just .211 this season with a .250 on-base percentage. He has stolen 12 bases, too, but he's been caught a Major League-leading five times.
Mattingly went through a list of other possible options for the leadoff spot but noted each had a drawback that leaves Gordon as the obvious choice.
Newly acquired outfielder Bobby Abreu could lead off, Mattingly said, but that would take a potent bat out of the middle of the order. Second baseman Mark Ellis could bat first, but Mattingly likes him in the two-hole, hitting ahead of Matt Kemp and Andre Ethier, and doesn't want Ellis' role changing on a day-to-day basis.
"He kind of needs to be that guy," Mattingly said of Gordon. "I know we can't force a square peg into a round hole, but we have been able to sustain so far without Dee kind of getting going."
Left fielder Tony Gwynn Jr. got the start on Sunday afternoon in the leadoff spot, but as a platoon player, Gwynn won't be in the lineup with Gordon very often. When Gwynn does play on the same day as Gordon, Mattingly said he'd be fully comfortable moving Gordon down because of the speed and on-base ability Gwynn brings to the table.
Another option is moving A.J. Ellis higher in the batting order. Ellis, a catcher, has been one of the Dodgers' best on-base percentage guys at a .455 clip this season, but he isn't close to a threat on the basepaths.
Mattingly dismissed that notion, saying he is content with leaving Ellis lower in the lineup, where he can drive in runs and turn the order over.
"You try to have a balanced lineup where you have a chance to score in all parts of the game," Mattingly said. "Obviously the more guys you've got that are productive, the easier that is."