Why would you trade pitching for pitching?

DALLAS - Some fans have asked why the Orioles would trade pitching for pitching, as for instance moving Jeremy Guthrie and getting a pitcher of Guthrie's ability back in return. Isn't that just swapping one deck chair for another? One reason to do that would be to get a pitcher that is younger and perhaps less expensive. Before you go saying, "There the Orioles go, going cheaper again," that move could be smart and they could use the savings in another area. Of course, under the above scenario, you would guess the team trading the younger pitcher would have an opinion that Guthrie would be an upgrade for them or maybe they just want a pitcher with a more experienced track record than the one they gave up. I floated a theory to a scout here that maybe the Orioles could get two young prospects for Guthrie, but he didn't feel Guthrie could bring that price in return. I'm sure the Orioles would prefer to deal a non-pitcher for pitching help to add to their staff and not have to do a one for one swap, but with so many clubs seeking pitching they may not be able to pull that off. So there is one reason why you might trade a pitcher like Guthrie: to get another pitcher or pitchers. To possibly get younger or save a few dollars to spend elsewhere.