A sprained left ankle will likely keep Richie Marquez, right,
out of Tuesday's U.S. Open Cup quarterfinal with the Red Bulls.
(Times Staff/TOM KELLY IV)

The Philadelphia Union travel to Red Bull Arena Tuesday to tangle with New York in a U.S. Open Cup quarterfinal that is all kinds of weird. In addition to the heat and 4 p.m. start time, the Union bring plenty of peculiarities to the table as well. Here are a few of the major oddities that manager Jim Curtin discussed prior to training Monday.

- Injury update: Following the injury that forced him to leave Saturday's game with Toronto, Andrew Wenger underwent concussion testing this morning before training and didn’t start the session on the field with his teammates. That doesn’t necessarily mean that he failed the protocols, though. In Curtin’s words, “He’s feeling better, but he has to be symptom-free for us to even have a shot to start talking about him getting back on the field.” All those qualifiers mean he’s doubtful, at best. Richie Marquez’s ankle will likely keep him out Tuesday. Curtin: “His left ankle is pretty swollen right now. He says it feels OK, but I just saw it. It’s not pretty. There’s some swelling and some blood on there, so looks like maybe out for tomorrow and possibly maybe back for D.C.” Curtin labeled Cristian Maidana’s knock against Toronto FC as “just a big bruise” on his foot that shouldn’t affect his status.

- Curtin said that the Union attempted to appeal CJ Sapong’s red card, but the petition got nowhere. “We tried to appeal that but there was no process, really, that goes on in the Open Cup, so they would not listen to any … as bad as the call was, they didn’t want to hear anything,” Curtin said. A reminder of what a borderline call that was.

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— Kevin Kinkead (@KevinKCBS3) July 20, 2015

- The Union remain in search of a backup goalkeeper for the tie. John McCarthy will start, but Brian Sylvestre is Cup-tied to Carolina and Andre Blake is away with Jamaica, where he’s fallen in the depth chart to third. (Dwayne Miller started all three group games, but was injured in the finale against El Salvador, replaced by Ryan Thompson, who started the quarterfinal win over Haiti.) That leaves the Union looking for just about any non-Cup-tied pro to sit the bench. The scenario of a keeper-less bench is in Curtin’s view “the worst-case. (It’s a) possibility obviously, but John will be called upon to play a good game for us. We do want to try to find a solution, but we do need a second goalkeeper.” In case you’re wondering, Rais M’Bolhi is not an option, per Curtin.

- One other thing to consider for the Open Cup, from section 203, paragraph A of the Open Cup handbook:

“A team may list up to 18 players on its game day roster. Professional teams may have no more than 5 foreign players listed.”

Those spots are used up quickly by the Union, especially with three Americans (Wenger, Marquez, Sapong) absent. Assuming that Vincent Nogueira, Maidana, Fernando Aristeguieta and Eric Ayuk make the 18, that leaves Curtin with a choice between Steven Vitoria and Fabinho. A back four (left-to-right) of Fabinho-Ethan White-Maurice Edu-Ray Gaddis or Sheanon Williams-Vitoria-Edu-Gaddis seem to be the two options.

- On the transfer front, Curtin confirmed that the trial for Salvadoran forward Rodolfo Zelaya has ended and that the Union won’t be pursuing him this window. There’s more optimism with Santiago Dittborn, the Chilean midfielder who trialed two weeks ago. Curtin didn’t divulge much info on Dittborn, but reading between the lines, Curtin often falls back on the clichés as a way to say something without giving too much away. Here are the quotes in full:

“Zelaya, he’s a very good player, a player that we’ve tracked for a while. Obviously Dallas had him in as well. They have him on their list, so if anything was going to be done, we would’ve had to come to an agreement for them first. They’ve already talked about bringing him into preseason next year, so they obviously have interest. Both teams would probably say the same thing: Good player, not fit right now, not as fit as he was when he was going well for El Salvador in the Gold Cup (two years ago). But you see flashes. Right now, we’re not going to move forward with him, but a player that’s still on our radar.”

On Dittborn:

“It’s still something we’re looking (at). It’s the time of the year where we’re looking to upgrade our roster in a couple of different spots. We’re always looking to improve. We’re not happy with where he are in the table with a group we think can be pushing for a playoff spot, so we’re always looking to improve.”