Really. What choice does he have. 

Go back to Siemian? The guy's shaken, possibly injured, and never was an elite player to begin with. 

Go with Lynch? Against the Patriots? We are bad-off but we're not out of it yet. Plus he's still recovering and relearning the playbook. 

Get some extra QB? What options are out there? RG3? Colin Kaepernick? Hell, force Tony Romo out of retirement? Even if we did take a risk on either of these players or one of the other no-namers, we still would need time to get them trained up. And it doesn't really matter at this point. QB is just one position out of many with serious problems, and after last week, not even the Defense is safe from criticism. 

Finish the season out with what we have. Play Osweiler one last time in the hope that we can pull a miracle out against the Pats and maybe salvage our season. If that fails, and we're 3 and 6, it's likely even a 10 and 6 record won't make the playoffs in this division, so let Lynch play then.