This is Keenum's team. Kelly hasn't shown anything that would suggest he will supplant Keenum as the starter. He could be the future of the franchise, but this is his first training camp. If Lynch is cut, there's already talk of signing a Vet to backup Keenum or possibly trading for one.
What has Keenum shown so far?
Small sample size, but if we are going to judge Kelly on his 2 preseason games then we should be able to judge Keenum. which QB has played better so far:
QB A: 21/30. 267, 3 TD, 1 INT, 116.9 rating
QB B: 9/17, 83 yards, 0 TD, 0 INT, 66.5 rating
Furthermore, take Keenum away from the MIN offensive line and his stats prior to joining MIN were not that great either.
What's interesting is Keenums completion percentage and QB rating are closer to his days in HOU and LAR than it is to his time with MIN, suggesting that it was more the team that lifted up a bad QB.
IMO you have it backwards, Keenum has shown nothing that he deserves to be the starter so far. I admit, it's a small sample size, but so far it has been more pre 2017 than 2017 Keenum. I'm not saying bench Keenum, it's his team at this point, but it has to be concerning that Keenum is playing like he did in HOU rather than in MIN so far. Hopefully he turns that around for the regular season.
With regards to the second bolded, all I can find is speculation that Denver will add someone, and Elway saying "we are evaluating that." Granted, it's not Elway shutting the door on the possibility but it's not him saying yes we are going that route.
If they do sign a vet, or trade for one, that QB has a large learning curve. We saw Sammy Watkins struggle for 2017 when he was traded to LAR right before week 1, what can we expect from a QB?
Needless to say, if Kelly keeps playing at such a level as he has, they won't need to go out and sign a QB2.