CHESTER, Pa. – Philadelphia Union midfielder Zach Pfeffer was hoping for a memorable game in what was only his fourth career MLS start.

And it was memorable. Just not in the way he planned.

The 20-year-old Pfeffer – who, in his fifth season as a pro, is finally starting to emerge as an important player for Philadelphia – was sent off with a straight red card in the 42nd minute for an elbow to the head of Mauro Diaz, completely changing the trajectory of Saturday’s game vs. FC Dallas and resulting in a frustrating 2-0 Union loss.

Afterwards, Pfeffer adamantly stated that the foul was unintentional.

“I watched the replay in slow-motion plenty of times and I realize on the replay that it doesn’t look great,” Pfeffer said. “I explained to my teammates that there’s absolutely no intent whatsoever. I was going so fast, I don’t think there was time to slow down, and I slipped a little bit.

“I was trying to get around him and bump him off the ball. I don’t think it helped too that he’s a shorter player. If it happened to a guy like Blas Perez, I might have hit him in the shoulder.”

The red card came as awful timing for the Union, who were tied with league-leading Dallas through one half and were seeking a key home win after suffering two straight disappointing draws to start the season.

In both of those ties, the Union felt harshly judged by certain referee calls. In this game, Curtin was far more understanding of the call but was still not entirely pleased by the process.

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“It was premature to immediately flash the red; maybe calm down and ask your fourth [official] and your linesman, who are right in front,” Curtin said. “I think that may have been the better decision. If they concur and it’s a red, then you go that way. But I think it was a bang-bang play.”

The most disappointing part for Curtin is that he would have liked to have seen how Pfeffer – and a full-strength Union side – might have played in the second half.

The Union head coach was happy in the first half with Pfeffer, who he said “earned” the start in place of the injured Cristian Maidana after a great preseason. The 20-year-old midfielder has now played in all three Union games this season after combining for just nine total appearances through his first four years in MLS.

“This isn’t obviously how he wanted it go,” Curtin said. “I thought he made some good plays. He showed that he’s dynamic on the ball. He had a good chance when he got one-on-one with the goalkeeper. … It’s a shame it got cut short.”

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Pfeffer, too, was relatively pleased with how his first half looked, as the 20-year-old made a nice play in the box to put a shot on net while taking four corner kicks. And while the untimely red card certainly spoiled the night, he doesn’t think it will hurt him or the team moving forward.

“I was happy with how the game was going, both for myself and collectively as a team,” Pfeffer said. “We were doing well, creating some opportunities to score and we almost put a couple in the back of the net. For that reason, it was disappointing to see a red card and get sent off.

“But we’re going to come together. We always stick together as a team. We have a great locker room.”

Dave Zeitlin covers the Union for MLSsoccer.com. Email him at djzeitlin@gmail.com.