Montana was probably the best quarterback in his era of playing football. Then he retired and Steve Young came from out of their system. Between the two of them they won a combined four Super Bowls and are probably considered the best quarterbacks to come out of a team one after another ever.
The same is true today in that Tom Brady is without a doubt the best quarterback of the present era winning three championships this decade. With the acquisition of Randy Moss last year Brady to Moss broke records held by the greatest players ever, and almost won another championship if it had not been poor play by the defence and the coach. What he has done in his career is amazing, but this year he was struck with a season ending injury.
With the weight of the entire northeast on his shoulders the backup and very young Matt Cassel was named the starter of the most successful franchise in sports in recent years. He came in and did what it took to go 11-5 in a year that was filled with great surprises and great teams. Had the Patriots made the playoffs we would have seen a Cassel poised and dangerous down the stretch.
At first Cassel was doing just enough to get by, and the patriots were barely winning games against bad teams. As the season went on however Cassel grew into one of the best quarterbacks in football. By the end of the season Matt Cassel was carrying the team.
He had two games of more than 400 yards in a row, something that Brady has never done in his years as QB. Had Matt been playing as well as he was at the end of the year the whole year, his numbers would have been some of the best in the league. Cassel has truly grown into a very good quarterback, and any team like the Tampa Bay Bucs or Chicago Bears would instantly make the playoffs.
Brady has been compared to Joe Montana ever since he won his first ring, and looking at them they are alike. Now Cassel may not be completely like Young, but there are similarities. This also is a similar situation because When Montana left Young had a huge gap to fill, and nobody really knew what he would do.
He was masterful, and took advantage of the best player in Jerry Rice. Cassel has had to fill the same kind of shoes this last year and used Brady's favorite target to his advantage in Randy Moss. Although Cassel still has to prove himself in the playoffs, from what he has been allowed to show, he can get the job done just like Young.
Now unfortunately for the Patriots they have a very tough decision to make. They either have to Stick it out with Brady (still the best in the game) or continue to train Cassel into an elite quarterback (which they could). In a perfect world they would like to keep both but that's not going to happen.
Brady has five more years of being an effective quarterback (assuming he comes back perfect from this injury), and he is only five years older than Cassel. If you do the math you figure that in five years Cassel will be as old as Brady is now. That means that Cassel would have about the same amount of time Brady has, five years. That is hardly worth it for Cassel career would be much better suited somewhere else.
Another point as to why they cannot keep them both is that Matt is a free agent, therefor he is going to want some money, probably to the point where he would make as much as Brady. This would not be smart to pay your backup quarterback that much money, and chances are he would not be happy.
The only reason the Patriots could keep Cassel is if they offered him a very fat one year contract to stay in case Brady cannot come back for the season. If they did that though they would once again be paying two quarterbacks the same money.
The Brady, Cassel vs Montana, Young may only have one serious knock on it. Cassel most likely will end up on a different team, and perhaps bring them to a Super Bowl win, and that's the one thing that differs. Montana then Young right afterwards was amazing, but if Cassel goes to a different team then that still leaves the two 49ers all by themselves perhaps for many years to come.