This is the best explanation of the QB platoon that I have seen. Most of the time no one goes into detail about how and why this platoon occurred, and how Brady actually won the full time job before the season ended.
The education of Patriots' Tom Brady
...except he completely left out Dreisbach, a former starter whom Brady split time with through the Syracuse game. The 1998 battle wasn't just a two-way affair between Brady and the freshman; it was a three-way including the guy who started much of '95 and all of '96 except the bowl. For all of pre-season fans were 100% sure Dreisbach was the '98 starter, and it was him that Drew Henson slappies like me were hoping he'd replace.
Per stats.ath.umich.edu, Dreisbach's stats against Notre Dame in 1998 consisted of exactly one rush for a three yard loss, while Henson threw 8 passes and had a single carry. See here for the box score against Notre Dame. Other than that, Henson threw a pass against Wisconsin and had a pass and a carry against Wisconsin. That does not suggest that Dreisbach had any significant playing time.
None of us can say we KNEW this Tom Brady was in that Michigan uniform! If you go back a watch his performance at the NFL Combine, check it out, there is a reason no one picked him until the PAT's took a chance on him!