Comparisons between Beltre and Donaldson are not especially obvious, but the more I watch Donaldson the more I see similarities. Both swing hard, don't get cheated, but also make a lot of hard contact and belong in the middle of the order. Both have exceptional reflexes and hand-eye coordination at 3B to go with a strong arm.
In a sense, one might argue that Donaldson is a "poor man's Beltre" at the plate in some ways, and is a "poor man's Beltre" at 3B. Now if Donaldson were really to be a .326/.400/.543 hitter, as he is so far in 2013, one could remove the "poor man's" label. But Beltre has a heck of a track record whereas Donaldson has had a whale of a two months following a very good second half in 2012.
But there are also a couple other key differences between Donaldson and Beltre and they are very much in Donaldson's favor. Donaldson is 27, while Beltre is 34. Also, Donaldson makes $492,500 this year, Beltre $16,000,000. Next year, Beltre will make $17,000,000, the following year $18,000,000, and Donaldson...won't.
Right now, both the A's and Rangers have 3Bmen who give you "gold glove caliber defense" at 3B and who are explosive at the plate. No doubt Beltre is the better career player in that he figures to retire with credentials that will make him a topic of conversation around Hall of Fame candidacy.
But who would you rather have going forward? These are two careers that appearing to be crossing: Donaldson coming from down low and being on the severe upswing, Beltre coming from a high, high level but entering years that figure to include a steady decline -- and it's right now that the two are looking to be pretty darn comparable not only in style, but also in value.
Over the next 4 years, during which time Beltre will be 35-38 and Donaldson will be under contract control, I'm thinking Donaldson has a really good chance to be the better player -- and he sure as heck will be a lot cheaper. Go figure.