Harrison Smith didn't play in 2007

He redshirted that year.

You're referring to the 2009 Michigan game. It wasn't Harrison Smith who missed the tackle.

It was Brian Smith who missed an easy tackle after Darius Fleming had flushed Forcier out.

If anything, Harrison Smith had a very good game in 2009, with 11 tackles, 1.5 TFL, despite being forced to jailbreak blitz on almost every down.

Link: https://mgoblue.com/sports/football/stats/2009/notre-dame/boxscore/2804