Seems to be a little bit in and out, but injuries have also played their part.
This season only:
01/09/17 - Qualifier v Ecuador (H) - Miranda started, Silva came on in his place at half time
05/09/17 - Qualifier v Colombia (A) - Started, subbed off deep into 2nd half injury time (to waste time? Rodrigo Caio came on)
05/10/17 - Qualifier v Bolivia (A) - Started alongside Miranda, got taken off injured in the 29th minute (Marquinhos on)
11/10/17 - Qualifier v Chile (H) - pulled out of the squad because of the previous injury
10/11/17 - Friendly v Japan (A) played the full 90 alongside Jemerson
14/11/17 - Friendly v England (A) Unused sub (Miranda and Marquinhos started)
Miranda looks like his main competition. Perhaps we could read something into him and Jemerson playing against Japan and not England as Brazil prioritising for the bigger game? Might be reading too much into it though as it could've just be semi-random squad roatation. Russia today for them, Germany on Tuesday. Might be worth looking out to see if something similar happens as the Germany game is obviously the big one, although Marquinhos apparently has a slight knock so that could also play a part in who they go with.