Mitchell was handed a $7,875 (£5,000) fine for taunting while St Louis Rams quarterback Sam Bradford was down injured during last weekend's match between the two sides, bringing Mitchell's grand total of fines for the season to almost $45,000 (£28,000).
The 26-year-old revealed that he went unpunished for a similar action earlier in the match and believes that his physical approach to the game is the reason behind his disciplinary record.
"Roger being Roger, I guess. To be honest, I think there is a little bit of a targeting system they have out," Mitchell told reporters. "I think I'm one of the guys they'd been looking for, but I'm okay with that.
"So obviously there is a bias there, there was a quarterback injured on the play and they want to fine me for that. If you're going to fine me for the act, then fine me for both of them. Since you didn't, though, Roger, don't come back and try to fine me. I'm just being targeted because I play football and am physical.
"I'm not out here cheap-shotting guys or doing dirty plays like you've seen people from Detroit do. I'm not going to name any names, but I'm not out here doing those things, so why I'm getting fined I have no idea. I'm going to keep playing my game. It's working for our defence. As long as I'm not getting penalties, then I'm fine with this.
"The coaches and my teammates know who I am, know the type of player I am, and I've definitely cut down on the personal foul penalties. So as long as I'm not getting flags that are hurting the team. Like I said, they have a little bit of a target on me. As long as it's not hurting our team, I don't mind."
Despite the fines, Mitchell is refusing to change his playing style and fully expects to be penalised by the league authorities again this season.
"Well, there's going to be [more fines]. We have nine games left. I'm not going to change the way that I play. I'm not getting penalties, I'm not playing dirty, I'm not hitting anyone to the head," he added.
"If you want to fine me on these little judgemental things, keep them coming. It's a write-off."
Mitchell's tackle on Sam Bradford resulted in the Rams quarterback being ruled out for the rest of the season with a torn ACL.