Le Toux is a major player to have to replace, but more moves are coming. On Wednesday, the Union traded midfielder Kyle Nakazawa and a 2013 natural second- round draft pick to the Los Angeles Galaxy for an international roster spot.
MLS teams are allowed to have eight international players, but they can increase that number if they acquire international spots. So the Union have an international spot open, and no doubt it will be used to bring in more firepower.
Those who think the Union are in dire straits with the 20-year-old MacMath replacing the 40-year-old Mondragon in goal may want to think again.
Mondragon brought a lot to the team, including confidence, stability, veteran savvy, and the occasional great save.
At the end of last season, we advocated that MacMath play more games this year, based on his own play late in the season, and on Mondragon's as well. Mondragon was susceptible to the low shot, and it appeared Major League Soccer teams were exploiting that in the second half of 2011.
Again, Mondragon's contributions were numerous, but MacMath proved to be a more-than-capable replacement after the veteran suffered a broken finger late in the season.
Here were the regular-season statistics - Mondragon 1.06 goals-against average in 27 games, all starts. MacMath - 1.07 goals-against average in eight games, seven starts.
And remember, MacMath allowed four goals in the first half of his first start in a 4-4 draw with New England in a game in which the defense went sleepwalking through the first 45 minutes.
MacMath gained the confidence of his teammates last season, and it has carried over as the Union began preseason workouts this week.
"Faryd did a great job and was an incredible leader, but Zac is a young kid, and he moves better and he is the future," said defender Danny Califf, who will be replacing Mondragon as the team captain. "Mondy has those intangibles you can't teach, but Zac has that youthful enthusiasm."
Now MacMath also has the confidence needed to assume his new role.
"Every single one of those games helped my confidence and helped me understand the games more in MLS, and I think I will take a bit of the experience into [this season]," MacMath said.
The only problem - other than injury - could occur if MacMath is picked to play on the U.S. Olympic team.
The only other keeper on the club is trialist Chase Harrison.
Team manager Peter Nowak made it known that if another keeper arrives, it won't be to unseat MacMath, who was the No. 5 overall pick in the 2011 MLS draft.
"The burden is big, but I think he can handle it without any problems," Nowak said of MacMath. "There isn't going to be speculation who is No. 1."
He doesn't want MacMath looking over his shoulder.
"I think it's important to know the whole team, not only us as a coaching staff, is behind him and will help him as they did last year," Nowak said.
The key is that the team's strength is the defense. Califf and Carlos Valdes are a strong central defender combination. Califf also raved about newcomer Porfirio Lopez, who is a left-footed kicker. The other outside back, Sheanon Williams, was among MLS's most improved players.
So MacMath, like Mondragon, won't have to do it by himself.
The team's defense and goalkeeping appear to be in good hands.
Stay tuned on the task of finding a consistent finisher.
Contact staff writer Marc Narducci at firstname.lastname@example.org, 856-779-3225 or @sjnard on Twitter.