Well, Mackanin hasn't said anything, Tom81 (who would also like to win this year) did. Klentak seems to want another OF bat just as much as his manager does. And while the manager should always decide who plays, there is nothing wrong, especially at the beginning of the year, with the GM setting a few ground rules (though, if a GM can tell you to play people for development reasons, he can also tell you to play his failing expensive free agents).
I think Mackanin will get the extension 'cause it's only money and the lame-duck thing does become a distraction. But he surely has to know - and if not Klentak needs to tell him - that his chances of being here in 2018 are more related to Allentown's criteria than W-L.
Anyway, 40% of the games is 65 games. Assuming perfect health for both catchers Knapp won't play that many, but he'll play 45-50. No big deal, and no reason to limit Rupp to 100 in just his second season as the starter (arguably his first as the clear-cut starter). And if Mackanin (and Klentak) were really all about winning now they might not even be sticking with Rupp (based on last year's various criticisms of him).