1 and 2 mean the same; the nonfinite clause is a sentence adverbial in both. The 3rd is simply improperly punctuated: it needs a comma after commander, as in #2. There is only one commander, so the nonfinite clause will be nonrestrictive in any case-- and remain adverbial in function.
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CalifJimI was going to say the same thing.Hi, CJ, It's only one commander that speaks on behalf of the troops under him.
Or maybe it was supposed to be commanders, since it says their?
CJ