Kaepernick was tackled while out of bounds by Clay Matthews during his side's 34-28 win win over the Green Bay Packers in the NFL, sparking an angry reaction from Staley that led to the 49ers reverting to a third down when they would otherwise have had a first down.
The Packers, and Matthews in particular, had spoken of their intent to target Kaepernick before the match, and Staley admits that his reaction was partly influenced by the pre-game comments.
"I'll try to do a better job just keeping my cool. I didn't want see Kaep get nailed like he did out of bounds," Staley told The AP.
"That's our guy out there. I'll protect anybody. Anything I feel like is outside the rules.
"Some of it was the comments he made this week about going after the quarterback. I wanted to grab him and let him know that's not going to fly. That's all I did."
Staley's penalty did not harm the 49ers in the end as they scored a touchdown on the very next play, although as both offenses were dead ball, the down should have been a fourth and not a third which could have resulted in a field goal attempt rather than a touchdown.