CHESTER, Pa. – How tough has this year been for Freddy Adu?

Even when the Philadelphia Union forward plays very well, it seems he has to come out of the game early than he would like.

That’s what happened Sunday when, after scoring twice to propel the Union to a 3-1 win over the visiting Houston Dynamo at PPL Park, Adu left with what was later classified as a minor quad strain.

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He suffered the injury while taking the penalty kick that put Philly ahead for good in the 50th minute, saying he felt a pull right below his left hip when he changed direction on the PK attempt at the last minute.

He tried to stay in the game but wasn’t able to run it off, leaving the match for Keon Daniel – who, coincidentally enough, also got hurt and had to make an early exit.

“Trust me, I really wanted to be out there,” Adu said. “But sometimes you’ve got to take care of yourself, too. I’m just glad we won the game.”

Before coming out, Adu was arguably the Union’s best player, scoring the game’s first goal by keeping a Ray Gaddis cross in play along the end line, making a little deke, cutting it to the right and then slotting home a shot through Houston defender Kofi Sarkodie’s legs and past goalie Tally Hall to the near post.

Adu said he was thinking about playing in a cross before realizing his best play was to take on Sarkodie one-on-one.

“I couldn’t let the ball go out of bounds,” Adu said. “I wanted it so bad. When the ball goes to the outside, [Union manager John Hackworth] has been very adamant about me and Josué [Martínez] getting into the box.”

After scoring on the PK attempt, Adu has now scored five league goals this season, plus three during the US Open Cup. Still, the season has been a trying one for Philly’s most well-known player, who hasn’t produced as much as fans have expected and often gets subbed out earlier than he likes.

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Perhaps his most memorable early exit came in May when he was putting on an electrifying dribbling show vs. the Red Bulls before getting sent off with a pair of yellow cards.

“It happens a lot to me – I do feel like that, yeah,” said Adu when asked about how his best performances are often cut short. “It is very frustrating. But this is due to different circumstances. Health is your No. 1 priority. You want to live to play other games and you want to be able to play them at 100 percent. I could have made it worse, I really could have. … I had to make a very tough decision in coming out.”

Adu wasn’t immediately sure the severity of the injury but was hopeful it wouldn’t be too much of a setback, especially coming off his first MLS brace with the Union.

“Hopefully I won’t miss any time,” Adu said. “That’s my goal. But I’m also not going to rush back and make it worse.”

Dave Zeitlin covers the Union for MLSsoccer.com. E-mail him at djzeitlin@gmail.com.