The ceremony included five ceremonial first pitches thrown by five members of the first-response team sent from Houston to New York after the attacks.
Astros players Brian Bogusevic, Justin Maxwell and Chris Snyder and former Astros player Jose Cruz visited four different area firehouses earlier in the day and signed autographs and presented a framed, autographed jersey to firefighters.
"It was a lot of fun," said Bogusevic, who was a senior in high school when the attacks occurred. "Putting it in the context of today being Sept. 11 made it a little bit more special. It makes you really appreciate what they do, and on a day like this, you appreciate it even more."
Maxwell was a freshman at the University of Maryland when the attacks occurred and was glad to be able to spend some time with firefighters Tuesday. He even brought his kids along.
"It's amazing what they do, and I'm grateful for them," he said.