It's not often that you see a guy that was just a special teams and role player his first three years end up in the HOF. You could see his potential and intensity his first 2-3 years. The Rams had really good OLBs then with Mike Wilcher and Mel Owens so it was hard for him to crack the lineup. He was a beast by year 4.
Maybe starting two AFC title games and a Super Bowl for Pittsburgh- plus the city's intensity for the team- swayed him to Pittsburgh.
I remember being at the game vs. Pittsburgh in 1993 when his return to Anaheim was being hyped and Jackie Slater totally stonewalled him all day.