Evans' availability was cast into doubt when he was struck in the side of the head by a close-range Kei Kamara shot during Saturday's game against the New England Revolution. Evans immediately went down and was ultimately replaced by rookie Tony Alfaro.
Even if Evans is able to play, the Sounders' center back depth is already being tested. Fellow starting center back Chad Marshall reportedly traveled with the Sounders for this East Coast trip, but was left off Saturday's roster and has now missed two straight games with a hamstring injury. It remains unclear what his status is for Wednesday's match.
A starting lineup with neither Marshall nor Evans would almost certainly feature Alfaro and Zach Scott. Alfaro played well in Evans' place, but he's also got just one MLS appearance. Scott's performances have ranged between strong and downright awful.