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During last week's discussion about Brett Wallace, I started thinking about the defensive comparison between first base and third base. It seems to be generally accepted wisdom that 3B is significantly harder to play than 1B, for a variety of reasons. Certainly a strong and accurate arm is a requirement at the hot corner, while a poor arm on a first baseman wouldn't have much of a negative defensive effect at all, since a first baseman rarely has to make a throw.
People also throw the word "range" around when comparing the defensive requirements of the two positions. Specifically, it's commonly believed that a third baseman needs to be much more mobile to his sides to be an adequate defender.
Is that really true? It seems to me that both corner infielders need to cover about the same amount of ground, laterally. Am I wrong in this assumption? Does the second baseman usually play closer to the first baseman than the shortstop plays to third, decreasing the number of plays the 1B makes relative to the 3B?
Of course, there are also "tweeners" - if a ball is hit such that both the 3B and SS could field it, it's likely that the 3B would take it, since his momentum is going the right way to make the play. On the other hand, the second baseman would probably take a first-second tweener to avoid the awkward pitcher-covering-first-base scenario. So this is a point in favour of the "yes, 3B need more range" hypothesis, since it increases the amount of ground a 3B covers, and decreases the amount a 1B covers.
Also, we must consider platoons. Since most batters are right-handed, and batters tend to pull, the third baseman sees more ground balls than the first baseman. This doesn't have any effect on the AMOUNT of range required, but it does increase the importance placed on the fielder's ability to cover that range. A 3B with good range adds more defensive value to his team than an equally good 1B, simply because more balls are hit his way. On the other hand, a 3B with poor range hurts his team more than an equally poor 1B by letting more balls go by. Here's point #2 in favour of "yes, 3B need more range".
This was all a long way of wondering "why not put Wallace at third, because if his range is poor, it won't really make a difference, as long as his arm is adequate for 3B?" But the answer seems to be no, it will make a difference, and he should probably be playing first, especially if reports of his potential as an above-average defensive 1B are true. However, I maintain my position that it wouldn't hurt to give him some time at 3B every now and then, especially given the lack of 3B in the organization. If Wallace could play a passable 3B, it would give AA more flexibility in terms of roster construction, by giving him an option for a back-up 3B who is already in the starting line-up. It would also open the door to potentially-cost-effective platoon scenarios, such as: against RHP, a LH platoon 3B at third with Wallace at first, and against LHP, Wallace at third with a RH platoon 1B at first.
Anyway, I don't want this to turn into a Wallace discussion since that's already been had. The question I'm more interested in is the general comparison between playing first and third. It seems to me that a third baseman doesn't need to cover much more ground than a first baseman, but since he sees far more batted balls, a greater importance is placed on his ability to cover that ground. So yes, third basemen do need to have better range than first basemen. What do you think?