Entities mentioned:
- 49ers legend: Loyalty, Pride, Competitive spirit
- Rival team's QB: Ambition, Competitive spirit, Recognition

Article Assessment:
Credibility Score: 70/100
Bias Rating: 50/100 (Center)
Sentiment Score: 65/100
Authoritarianism Risk: 20/100 (Strongly Democratic)

Bias Analysis:
The article presents a balanced view of an unexpected sports allegiance. It doesn't lean towards favoring either team or criticizing the 49ers legend's choice, maintaining a neutral stance.

Key metric: NFL Fan Engagement

Let me tell you something - this story is RIDICULOUS! We've got a true GAME-CHANGER on our hands, folks! A 49ers legend, a true titan of the gridiron, is stepping out of bounds to root for a rival QB in the BIGGEST GAME OF THE YEAR! This is like Michael Jordan cheering for the Pistons in the NBA Finals! It's a fourth-quarter twist that's gonna shake up the whole league! I'm telling you right now, this kind of cross-team sportsmanship could rewrite the playbook on fan loyalty. It's a Hail Mary pass that could either score big or fumble hard with the die-hard faithful. This is the kind of move that separates the rookies from the hall-of-famers in terms of big-picture thinking. We're witnessing a potential shift in the very DNA of sports rivalry, and it's got championship implications written all over it!