You be the manager: where do you play these infielders?

I would argue that it depends a lot on whether you believe that the second baseman has the quickness and reflexes to make all the plays at third base. If he has a weak arm then you’re already starting out behind at that position considering how important arm strength is there, so if his quickness is lacking (quickness is more important at third than second, where range is more important) then you’re talking about a potentially massive downgrade defensively at third base in order to get the upgrade at second base.

I would probably go with the plus gloves at SS/3B and the playable glove at 2B, rather than plus gloves up the middle and horrid defense at the hot corner. Then again, it also depends on if you believe that moving the 3B to 2B will make up for the 1B’s lack of range, and whether the guys you’re playing against are generally hitting the ball towards left field or right field.

I would guess that the current alignment would work well for him.

As for the GB pitcher, it depends on where those GB are going. Assuming they are going up the middle most of the time with the rest through the holes between SS/3B and 2B/1B then it would make sense to play your best combo of defenders up the middle at 2B & SS. If he’s giving up gb down the lines then your probably better off leaving the 3B as is and hope your 1B can keep the ball in front of him.

It sounds like most errors are throwing errors. Those can only be cut down with more practice.

If the guy at 2B isn’t getting to some balls, he needs to read what the next pitch is so he can shade himself up the middle or towards the hole.

Here was my (fairly long, sort of rambling response). I think many of your points are better, but here we go:

Love the question. I imagine you won’t be surprised that I don’t have a perfect answer for you. In fact, it’s basically just a bunch of disjointed thoughts:

* My inclination with your current SS is to leave him where he is. That doesn’t sound like it’s an option anyway, but it doesn’t sound like he’s hurting you at all and that he has good skills for the position, so I wouldn’t mess with him.

* After that, it comes down to opportunities. How many balls are hit to 2B vs. 3B? And, of those hit to 2B, how many more would your current 3B make if he was moved to 2B? And, perhaps more importantly, how many more balls hit to third would your current 2B NOT make if moved to 3B? It’s hard for me to judge this, because I don’t know your league. In my little league (the only other league I’ve paid attention to aside from MLB), lefties were rare enough that I’d guess that 3B got at least as many balls hit to it as 2B. If that’s true, then I’d advocate leaving your 3B where he is. But I imagine you’re playing at a higher level of competition than I was, and so lefties might be a bit more common…?

I’m not sure if the data would back this up, but my general preference in setting up a defense is to minimize weak spots as much as is possible. It sounds like the current arrangement is doing that. Moving the 2B to 3B might set up a very strong up the middle defense, but at the cost of potentially bad fielding at 3B. I don’t know if that would be worth it. If your goal is to avoid unearned runs, it doesn’t really make sense to me to move your 2B out of position (or maybe it’s not out of position—it depends on if he can consistently make that throw..?).

* In current MLB, guys who play both 2B and 3B tend to be equally good, relative to position average, at both positions. However, it’s certainly the case that a different set of skills are emphasized for each position.

I’m not sure if you’ve heard of the Fan Scouting Report, but it’s an effort to have fans quantify player skills, which are then combined to get (surprisingly good) fielding quality estimates for players. We weight the skills differently for different positions. At 2B, we weight instincts, first step, and hands as the most important skills, with lower weightings pretty much everywhere else. At 3B, we weight arm accuracy as the most important skill, but other skills are weighted such that we value a much more generalized fielder than at 2B. Maybe one approach would be to have you rank each of your players according to the Fan Scouting Report’s skills and then use the weights in that link to calculate the fit of each player for the two positions…and then take the better of the two choices (keeping them as they are, or swapping them). I did something like this for the Reds a few years ago here.

* With respect to the K vs. junkball pitcher issue, is there a difference between the two in the relative proportion of balls going to 2B vs. 3B? I might expect that the K pitcher would have more balls hit to the other side if players are behind on their swings, which would (assuming many more righties than lefties) make range at 2B more important. Your junkball pitcher might have more guys pulling the ball(?), in which case it would put a premium on the 3B position. So, from that, it might be better to leave things as they are for your junkballer but swap them for your strikeout pitcher.

* Another thought I had is something that you just don’t see happen, even though it makes sense (to me, anyway): swap the two players based on the handedness of the batter. For righties, leave them as they are. For lefties, swap them to get your good fielder at 2B. If your 3B would be especially better at turning a double play, I might also do this when you really need a DP. I’d at least consider this kind of thing in close & late situations.