The Rockies had a desperate need for an additional starting pitcher with Aaron Cook out with a sore shoulder, possibly for the season, with internal options like Josh Fogg (not good enough to start for a contender) and Franklin Morales (pitching in one-inning stints for several months now) less than ideal to take Cook's spot. Thus, acquiring Jose Contreras from the White Sox is a better option than anyone currently in the Rockies' organization, although Contreras isn't the savior.
The best hope for Colorado is that Contreras benefits, as so many pitchers do, from moving from the American League to the Quadruple-A League, particularly the National League West, where three of the Rockies' four competitors have what might charitably be called mediocre offenses. Contreras still sits in the low 90s and might flash a 95, but his best approach is as a crafty righty who changes looks, speeds, and even arm angles to get hitters out; for example, he'll drop down to sweep a slider away from a right-handed hitter but will go back up to three-quarters to throw it at the back foot of a lefty. He also has a solid-average splitter that he should probably use more to keep hitters from sitting on the straight fastball, although there are a lot of NL hitters who can't touch 94 even when it's straight.
It's no guarantee, but with Contreras the Rockies at least get the possibility of a few strong outings down the stretch in a race that might be decided by just a game or two. In exchange for Contreras, the White Sox get fringy right-handed pitcher Brandon Hynick, but also get an open roster and rotation spot if they choose to call up their farm system's most pleasant surprise this year, right-hander Dan Hudson.
The Dodgers' pickup of Jim Thome might be partly due to GM Ned Colletti's known fetish for grizzled veterans, but Thome does have value to L.A. as an option off the bench. His bat speed has slowed and he's futile against left-handed pitchers, but he hits right-handers reasonably well and can crush a mistake from any pitcher, as his raw power is still present because of his size and strength. Although first baseman James Loney is suffering through his second straight disappointing year, Thome hasn't played first base in more than 24 months, and is so slow afoot that he'd likely be the worst defensive first baseman in the majors if the Dodgers asked him to try it, so that doesn't appear to be an option.
The Dodgers don't have to carry Thome on their postseason roster, but if they do, it should be at the expense of a 12th pitcher, as today's overstuffed bullpens mean you have to get as much value and flexibility as possible from your limited number of bench spots. The White Sox could use the open DH spot to give catching prospect Tyler Flowers a few big league at-bats; he's rough behind the plate, but still playable there, and a cup of coffee in which Flowers gets to face major league pitching without the extra wear and tear of catching is a great opportunity.
Los Angeles' acquisition of Jon Garland makes a little more sense. Garland is chronically overrated and somehow acquired the "ground-ball pitcher" tag despite never actually being a ground-ball pitcher, but he does do two things well: throw strikes and take the ball every fifth day. The back of the Dodgers' rotation has been an open sore all year, and Chad Billingsley and Hiroki Kuroda have both missed time with injuries, so adding Garland also gives the Dodgers the opportunity to back off on the workloads of those two starters if at some point they have six healthy starters on the roster (including Randy Wolf, Vicente Padilla and their de facto ace, Clayton Kershaw). Garland wouldn't make the Dodgers' postseason rotation barring an injury, but again, there's sufficient chance that either Billingsley or Kuroda won't be able to pitch in October, and having a better backup option than the erratic Padilla is good planning.
When I heard Monday night that the White Sox were having a closeout sale on veterans, I thought the Giants might take a shot at Jermaine Dye -- they don't get much offense from their outfield, or from any place other than third base, really, and Dye would be a huge upgrade in right field. There's some defensive risk with Dye -- who has lost about three steps over the past year or two -- moving to a big ballpark like San Francisco's stadium, but given how bad the offense is, it was probably a good gamble if the price on Dye was as low as it was on Thome and Contreras.