QB for Week 15 & 16

Got the bye this week so I’m looking for best match-up for QB for Week 15 & 16

I have Dak and Mariotta but Keenum, McCown and Carr are available, do I stand pat or pick someone up? Thanks

Week 15:
Dak @ Oakland
Mariota @ SF
Keenum home vs Cincy
McCown @ Saints
Carr home vs Dallas

Week 16:
Dak home vs Seattle
Mariota home vs Rams
Keenum @ GB
McCown home vs Chargers
Carr @ Philly