I'm going to lump 1st and 3rd together because I'm starting to realize if I really do this one position at a time I'm probably going to kill myself. I'm going to start with 3b because that's a little more clear cut - and it really comes down to if you believe Danny Valencia is the long-term solution or not.
After last season when Valencia finished 3rd in R.O.Y. voting and OPS+ed 117 optimism was high. Sure, his BABIP was unsustainably high but he had a little pop, looked like he could hit, and was a plus fielder both quantitative and qualitatively so it looked good. Then this year his fielding suddenly turned poor, he was a constant victim of mental lapses on a near Lew Fordian level, and all his numbers dipped slightly, hurt by a low BABIP. Basically we've seen 2 seasons of Valencia and they were complete opposites.
Because I'm not a psycho with an agenda it seems obvious to me that the truth is somewhere in the middle. I suspect Valencia is a slightly above average third baseman in every way - hitting and fielding, even if his baserunning sometimes makes me laugh like I'm at a Dane Cook show but I'm really just laughing out of pity. I would be completely ok with, and would actually recommend, the Twins roll out Valencia for at least another year. He's never been a great hitter, at least not since A ball, but he's been good enough the whole way through the minors and in his first 2 years with the big club, and really what's the other option? Luke Hughes? I like Hughes, but he's basically a younger Matt Tolbert with slightly more power and smaller nostrils. No, this needs to be Valencia's job until Miguel Sano's ready, and that's at least 3 years from now. Maybe less since Latin American birth records are always so accurate.
Now that that's settled we move on to first base, maybe the most confusing position on this team. You've got a part-time catcher in Mauer, a full-time outfielder who might not even be there next year in Cuddyer, and a prospect who has fallen out of favor but now looks good.
Cuddy is obviously not your answer so we'll wait to address him when I talk outfielders, so in my mind it comes down to either making Mauer your full-time 1B or giving the job to Parmalee. I talked enough about Mauer's batting skills in my catcher rundown, so we'll just jump to Parmelee.
Frankly, I like him. And I have no idea why I qualified that with frankly. He's an interesting case because he was a high pick who looked like he'd be a high power, low average guy throughout his early minor league career. Then a few years ago he started trending in the opposite direction with his average raising and his power dipping, and I read somewhere that I'm too lazy to go find that the Twins basically told him to cut down on his swing and hit for higher average, something they love to do to anybody who shows any power (ask David Ortiz or J.J. Hardy). Now that he's hit the majors yes his average is way up there (very high BABIP at .385) which is nice, but even better is he's taking a good amount of walks and showing a power bat once again.
There's a stat called "isolated power" which is calculated as slugging-average, and is meant to show a batter's power while taking out those whose slugging percentage is inflated due to a high average coming from a lot of singles. Parmelee is at .194 so far this year, which is his highest number since A ball in 2008 and is second amongst all Twins behind just Jim Thome (and, if you ignore PA requirements, Scott Baker which is LOL). It's not exactly elite to be a leader in power on the Twins, but with enough at-bats he'd rank 26th in the AL in that stat, ahead of guys like Nick Swisher and B.J. Upton - not elite, but guys with some pop. No doubt, he's hit the ball well.
In the most simple terms, Parmelee has looked good in his call-up and deserves the chance to be the everyday first baseman next season. Hopefully Mauer can catch more often than not and DH as well rather than taking the full-time first base spot from him. I don't know that I'm buying in that Parmelee can be anything more than an average first base bat but he has potential, and looking at the other options, both in the majors and minors, he's really all they have. The free agent crop looks either to be well out of the Twins price range (Fielder, Pujols if he hasn't signed yet) or Tony Batista, let's throw money at someone and hope they pan out types (Xavier Nady, Ross Gload, Brad Hawpe, Lyle Overbay). The only remotely interesting guy on the list is Nick Johnson and he spent all this year in Cleveland's minor leagues and managed to hit just .200. Still, I say they go with Parmelee as the starter and offer Johnson a minor league deal and hope for the best. Not that different than the Nady/Hawpe group, but Johnson should be ultra cheap and is a worthwhile gamble unless there's something going on with him I'm not aware of.
Much like the catcher position for next year, things look confusing with a side of depressing.