The middle linebacker, a cancer survivor, started the New York Giants' game against the Philadelphia Eagles on Sunday night, his first action from scrimmage this season. With his parents watching from a private box at MetLife Stadium, Herzlich replaced Michael Boley, out with a hamstring injury.
Herzlich, whose previous work in games came on special teams, had four tackles in a 17-10 loss.
At the outset, Herzlich felt nothing but thrills.
''When the national anthem was playing, and I was out and knew I was going on the field, I closed my eyes and thought, `This was happening,''' he said. ''So as long as I am playing football, I will give my 100 percent every game. That's where I have to give my 100 percent, doing the right thing every play.''
Herzlich, who was not drafted out of Boston College and made the Giants as a free agent, said Friday: ''This is what I've been waiting all my life for, just a chance.''
Herzlich starred at Boston College before he was struck with the disease after his junior season. He recovered and suited up for BC as a senior, but then went undrafted last April. He impressed the Giants with his diligence and aggressiveness in the preseason after they signed him as a free agent.
When Boley went down, New York's coaching staff had to decide between starting Greg Jones, another rookie who has been in the regular lineup much of the season, and Herzlich. They went with the inspirational Herzlich, but he was disappointed with his and the entire defense's performance.
Most annoying to Herzlich was the 80-yard drive that took up 8:51 of the fourth quarter and brought Philadelphia its winning touchdown.
''An 18-play drive is not really acceptable,'' he said. ''We know that as a defense. We can't keep putting our offense in that position, where they need to drive down the field to score. We need to make some plays and stop them.''