The 25-year-old arrived on a free transfer from MLS, having played for Orlando City, but scored just once in 15 games for the Capital club and returned to the USA in May with Chicago Fire.
When the twice-capped American forward left Hibs, it was suggested that he had struggled to adjust to the Scottish game.
On his return to his home state Mueller said: "I wasn't playing as much, it was really hard for me. It was more about the mental grind I was going through in terms of not getting the minutes that I wanted. The team wasn't doing particularly well either, we were losing a ton of games.”
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"It's a much higher-pressure situation and a different style of play. Much more direct, faster in terms of pressing and the commitment to defend.”
Speaking exclusively to the Evening News, Gordon said: "We were very optimistic with Chris. He came, and he certainly had the technical skill but the game here is fast and physical, and it takes time to adapt to that.
"In fairness to him, perhaps we didn't give him enough of a chance, or perhaps he didn’t get enough gametime.
"I think he lost some confidence, and then he had a chance to go back to the USA so that worked well for him and it worked well for us too.”
Despite Mueller’s move across the pond not working out the way either player or club wanted, Gordon insists that Hibs have to take risks if they want to grow as a club on and off the pitch.
"If you look at the values in our plan, we are a club that takes risk. We are a club that is willing to take risks,” Gordon explained.
"We will do things, and we will fail, but we'll do it again, and we will take risks again.
"You're not going to grow unless you're willing to take risks. We want to be innovative, and come up with different things in the game in Scotland and taking risks has got to be part of that.”