I think we're all pretty familiar with the struggles of Brad Miller. He hasn't been hitting. He hasn't been walking. Thankfully his defense has been pretty good which is keeping him in the lineup.
Problem is, there is a player in Tacoma right now whose reputation is that of an above-average defender at shortstop, and he's kind of killing it with the bat as well. Chris Taylor has a batting line of .361/.395/.583 in Tacoma. Since half the PCL has roughly the park factor of the moon, it's worth noting Taylor has a home line of .288/.350/.577. His ISO and BB% are both higher at home.
And Nick Franklin is narrowly outhitting Taylor which isn't surprising given the way Franklin was abusing AAA pitching prior to his callup last season.
So if the trajectories of these players more or less continue for the next month, or even if Miller begins hitting better, should there be any question who is the starting shortstop for the Mariners going forward? It should not. Rookie players generally experience difficulties as they adjust to the league and vice-versa and verse-visa. The whole team has been striking out like mad lately, not just Miller. Should Taylor or Franklin replace Miller as the starting shortstop there is no reason to think they would enjoy uninterrupted success the rest of the season.
But there is one scenario that ought to force the M's to make a change. There are a few teams around the league in need of a shortstop. They likely prefer a player with some kind of a track record of success in the major leagues. If the M's can deal Miller for a significantly more valuable piece than Taylor or Franklin will bring them, then they should consider making the deal, and filling Miller's spot with the better of the two guys currently in Tacoma. Personally, I see this as a serious possibility since the team is about to have a three-way logjam at the position. Teams apparently aren't beating down the door to trade for Franklin. And if Miller starts to hit again he'll probably be more attractive than Taylor.
This team may well be better off with Taylor starting at shortstop and a good center fielder than it is with Miller and Almonte / Saunders. Taylor does not have Miller's power, but should make up some or all of the difference with his defense and base running. The M's system doesn't even have a true center field prospect anywhere near the majors. If Miller will get the M's a good center fielder who can hit left-handed pitching, then that's a deal they should probably take. Obviously if they can make such a trade for Taylor instead, that would be the preferable route. But if it takes Miller, I would consider such a deal at this point.