Prior to Wednesday night's 2-0 loss to Sporting Kansas City, the former Arsenal star felt that his ex-Barcelona teammate Marquez, who has been sidelined due to suspension and injury at times this season, can have a positive influence on the team in the playoffs.
"I know it might be boring to you guys, I know some guys maybe might not like it, but the key for us to win MLS Cup is Rafa Marquez," said Henry.
"I told you so many times, I will repeat it. The only thing is he couldn't train because he was injured. But I will maintain it, on-form, it's another game for us, because the guys at the back feel like they can give him the ball all of the time, you deal with it.
"The passes he did to me (Saturday), or to Tim (Cahill), or his vision, the way he looks and calms the team down.
"As I said to you, if Rafa is fit, that was the most important thing, trust me. Scoring goals, Kenny (Cooper) will, hopefully I will carry on; that's not what we were lacking this year. We can score goals. But we were maybe missing Rafa a bit too much for my liking."