Source: Otto Greule Jr/Getty Images

Union goalkeeper Zac MacMath is listed in Tuesday's Major League Soccer injury report as 'OUT,' though his status for this weekend's league contest with New York is unknown.

According to Union boss Peter Nowak, MacMath -- who is suffering from concussion-like symptoms -- will sit Wednesday's friendly with FC Schalke 04.

MacMath sustained the injury in the first half of Saturday's 1-0 Union defeat, when Seattle's David Estrada struck MacMath in the back of the head while vying for a ball in the goalbox. MacMath remained in the match.

The second-year keeper, and first-year starter, MacMath has not had to miss action due to injury. The fifth overall selection in the 2011 MLS SuperDraft, MacMath owns a 1.125 goals-against average with three cleansheets this season. Two weeks ago, MacMath's franchise-record 408-minute shutout streak was snapped in a loss to San Jose.

Of course, if I hear anything, I'll be sure to update. This is all I have for now.