So Beckham, who is earning $6.5 million as MLS's highest-paid player, got the game off.
Of course, the Union realize that the Galaxy have many more weapons than just Beckham.
"We don't approach it like we want to beat David Beckham," said assistant coach John Hackworth, who will guide the Union while team manager Peter Nowak competes in a charity soccer game in his native Poland. "We approach it like we want to beat the Los Angeles Galaxy."
In their brief history, the Union are 0-3 against the Galaxy, including a 1-0 loss in Los Angeles on April 2. In the last two meetings, both 1-0 Galaxy wins, Beckham assisted on the goals. During the win in April, Leonardo headed in a Beckham free kick.
The Union (4-2-1) have allowed just three goals in MLS games this season, all coming off set pieces.
"They still have guys who swing balls in, and we have to be aware," Union defender Sheanon Williams said. "We have only given up goals on set pieces, and we have to get better at that and can't give up easy goals like that."
When asked whether Beckham's day off is injury-related or purely for rest, Arena said it was the latter.
"Rest, fatigue, bumps and bruises you typically get," he said Tuesday during a news conference. "Knowing we have a game on Saturday, we have to make decisions on players who will play three games, two games, that kind of thing. We decided to rest him."
Arena then took a shot at MLS schedule-makers when it was suggested that Philadelphia fans would be disappointed about missing Beckham.
"We're sorry about that," he said. "We didn't put together the schedule. Our job is to try to keep our players healthy and place the right players on the field each game to give us the best chance of winning."
Of course, the Union will have to stop Landon Donovan, who has scored his team's last four goals. Donovan acknowledged the difficulty of playing without Beckham.
"It is obviously going to hurt us," he said. "His qualities aren't easily matched by others."
Notes. Hackworth said that defender Danny Califf, who missed Friday's 1-0 loss at Portland because of illness, practiced the last two days and is ready to go. . . . Midfielder Stefani Miglioranzi, bothered by a groin strain, is listed as day-to-day.
Contact staff writer Marc Narducci at 856-779-3225 or email@example.com. Follow him on Twitter at Twitter.com/sjnard