Dustin Keller's 2013 season is over before it begins. (USATSI)
Dolphins tight end Dustin Keller suffered a season-ending knee injury in Saturday's preseason game after Texans rookie safety D.J. Swearinger went low to make a tackle. It was a perfectly legal play, but controversial nonetheless because a player's legs are his livelihood.

For what it's worth (and we would imagine not much to Keller), Swearinger apologized after the game, and offered a defense of his actions.

"With the rules in this era you've got to hit low," Swearinger said. "If I would have hit him high, I would have gotten a fine. So I think I made the smartest play. I'm sorry it happened and I pray he has a speedy recovery. ... Right now it's just instinct. You see somebody come across the middle, you gotta go low. You're going to cost your team 15 yards. You've got to play within the rules."

Dolphins wide receiver Brian Hartline is unimpressed with Swearinger's rationale for going low.

“It’s crap,” Hartline told WQAM’s The Joe Rose Show (via PFT).  ”I mean I think that, me personally, if you’re telling me, ‘Oh, I’m so worried about going high or hurt[ing] the head,’ you consciously went low then, is what you’re trying to tell me.”

Yes, that's exactly what Swearinger's trying to tell you, Brian.

This was then-Steelers linebacker James Harrison's explanation for hitting Broncos wide receiver Eric Decker low during a wild-card game in Jan. 2012. Decker was injured on the play but Broncos vice president of football operations John Elway conceded that Harrison's tackle was within the rules given the NFL's emphasis on reducing head injuries.

"The [tackling] target is now lower," Elway said at the time. "Harrison, because of the fact that he's been fined so often, really had no other option. ... I don't think he intended to hurt Eric. But obviously because of the situations he's been in, he had to go low and stay away from the head. And it ended up costing an MCL sprain for Eric."

As we wrote after Decker's injury, this is the unintended consequences of actions not thought through entirely by the league. Yes, the NFL should thrive for making the game as safe as possible, but drastic changes don't come without ramifications. And the league can't argue that knee injuries were unforeseen because players lamented the possibly as soon as the new rules were announced.

Still, Hartline isn't buying it.

"I have a lot of good pros on my team," he said, "and from what they have said to me is that there is no place for that in the game today."

Except that there is. Not because it's right, but because defenders are running out of places to hit a player when making a tackle.

We discuss whether Swearinger's hit was controversial on the latest Eye on Football Podcast. Listen below and while you're at it, subscribe via iTunes.