Ravens QB Joe Flacco out after big hit by Dolphins LB Kiko Alonso

— -- BALTIMORE -- Joe Flacco suffered a concussion Thursday after the Baltimore Ravens quarterback took a vicious shot to the head from Miami Dolphins linebacker Kiko Alonso.

Flacco looked glassy-eyed as he got up and held the left side of his face while he walked into the locker room for evaluation with three? minutes remaining in the first half.?

The Ravens' sideline erupted when Alonso's hit dislodged the helmet of Flacco, who was sliding after a 9-yard run. It also left Flacco with a cut on his ear that required stitches.

Baltimore coach John Harbaugh came onto the field yelling at Alonso, who was flagged 15 yards for unnecessary roughness.

Flacco was in the midst of his best game of the season. He completed 10 of 15 passes for 101 yards and a touchdown before leaving the game.

Ryan Mallett took over for Flacco, finishing 3-for-7 with 20 passing yards and one touchdown. The Ravens won the game, 40-0.?

When asked postgame whether he thought he'd be suspended, Alonso said: "That's out of my hands, man...it's a bang bang play, and I hope he's all right. I truly do."

Alsonso said there was "no way" he could have avoided the hit.

"When a guy slides, the target is very small. I just think it was a second late (Flacco's slide), which is why I hit him, to be honest with you, "Alonso said. "At first I was anticipating I thought he was going to slide. And then it got to a point where I was like, 'I got to him,' because he slid too late."

Harbaugh said Flacco received stitches on his cut left ear without anesthesia. "So, he's a tough dude."

On the Alonso's hit, Harbaugh said "I'm not commenting on that. It was penalized correctly, I would say."

Several Ravens players also expressed their frustration with the hard hit.

If you mess with one of us, you got to mess with all of us. We went out there and gave everything we had for Joe, the coaches and Baltimore," Ravens defensive tackle Brandon Williams said. "We had to let everybody know that you can't just mess with one of us and know expect to get hit 24 more times."

Ravens offensive lineman Ronnie Stanley said Alonso should have been ejected.

"For a hit like that, I think that's the right call for that," Stanley said.?

NFL rules allow any player, including quarterbacks, to end a play without contact by declaring himself down. Thursday night, Flacco attempted to do so by sliding feet first. In those situations, according to the NFL rulebook, the ball is dead "the instant he touches the ground with anything other than his hands or feet."

The rule instructs defenders to "treat a sliding runner as they would a runner who is down by contact" and "pull up when a runner begins a feet-first slide." It allows flexibility for a defender who might not be able to avoid contact, but still prohibits the kind of contact Alonso initiated on Flacco.

"If a defender has already committed himself," the rule states, "and the contact is unavoidable, it is not a foul unless the defender makes forcible contact into the head or neck area of the runner with the helmet, shoulder, or forearm, or commits some other act that is unnecessary roughness."

That's undoubtedly what referee John Parry saw when he penalized Alonso for unnecessary roughness. The rulebook provides referees with the option to eject players in situations in which the contact is flagrant, but Parry elected not to. The NFL defines "flagrant" as "extremely objectionable, conspicuous, unnecessary, avoidable, or gratuitous."

Al Riveron, head of officiating for the NFL, told CBS that the league would not? comment on the playThursday night not unusual; the league rarely comments right away, instead choosing to watch the film before talking about a ruling.

ESPN's Kevin Seifert contributed to this report.