ESPN's Adam Schefter is reporting that Marcus Mariota will have an MRI on his left knee.
<blockquote class="twitter-tweet" lang="en"><p lang="en" dir="ltr">Titans quarterback Marcus Mariota will undergo an MRI on the left knee he injured vs. Dolphins, as <a href="https://twitter.com/ProFootballTalk">@ProFootballTalk</a> reported.</p>— Adam Schefter (@AdamSchefter) <a href="https://twitter.com/AdamSchefter/status/655935589863174144">October 19, 2015</a></blockquote>
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Mariota stayed down on the field after the dirty hit from the Dolphins' defender, but he was able to stay in the game. Zach Mettenberger did replace Mariota late, but that was only after the game was out of hand.
The fact that Super Mario was able to finish the game is encouraging. Hopefully the MRI will show that there is no structural damage to the knee.
With all of that being said, if the Titans don't figure out a way to protect Mariota better this is not going to be the last injury he suffers. The offensive line is nothing short of horrendous, and Ken Whisenhunt refuses to leave one of the 5 tight ends he kept on the roster in to help while Jeremiah Poutasi is letting guys tee off on Mariota.