Money makes the world go 'round. A literalist might say it's actually a combination of angular momentum and gravitational forces, but in any trade in baseball, the discussion involves dollars, not Johannes Kepler. Trades in baseball are rarely just a player-for-player matter because significant consideration is given to the contracts that will also be swapped. Teams are usually reluctant to trade their young stars for very good reasons, so the principles in most deadline trades involve veteran players either on the verge of a new contract or with a substantial existing one.
Not every contract will work out for a team, of course. Even a contract that seemed like a good idea at the time has a risk of backfiring for the signing team. Using the ZiPS projection system, we ranked the least desirable contract burdens in baseball by the difference between the player's projected value (based on his expected current dollar value on the free-agent market) and what he actually is scheduled to be paid.
The Tigers may have made some ill-advised moves this past offseason (cough Doug Fister trade cough), but one good move they did make was unloading Fielder's contract to the Rangers with cash to pick up Ian Kinsler and his smaller remaining contract. Fielder's contract looked like a significant issue going into the season; he was approaching 30 years old and was coming off a down 2013 season. After he required season-ending surgery on a herniated disk in his neck, it's looking worse.