I didn't realize it today, but I just learned that Marte is a lefty.
Lefties rarely make it as closers, because managers tend to like to use lefties on a situational basis.
So in a weird way, this hurts Marte's chances of becoming the sole closer. Closer-by-committee seems like the more likely scenario.
(As a Marte owner, however, I hope I'm wrong.)
Everything you know is wrong.