Why does MJ Start over XSF?

[*ochocincos*]

XSF is being worked slowly back. I expect he'll see more snaps this coming weekend, possibly start.
What is more of a head scratcher is why not try BJ Finney, who has had a 70+ pass blocking grade every year he's been in the league, until XSF was fully back. Finney can play all IOL positions too, he isn't only a C.