We're coming up on baseball's trade deadline Friday afternoon; trades still can be made after that 7/31 deadline, but players need to clear waivers to be traded after that, so a team that wants to effectively veto a trade can claim the player they'd rather not see go to someone else and force his current team to either let him go to the claimer or pull him off of waivers.
Thus, any big deals need to be done before then. Free agency has added a wrinkle to such trade-deadline deals. Teams that have players on the last year of their deals might be tempted to trade them in late July and get something for them rather than lose them come next year and get either nothing or next to nothing (net losers in free agency do get some draft picks, but not as much as they'd get in a trade in most cases).
That temptation is stronger when a team is have a bad year and is out of contention for the playoffs by late July; those teams will be sellers, while teams in the pennant race will by buyers, "renting" the prospective free agent for two months plus the playoffs in return for prospects . Teams that are almost out of contention are in the cusp of what the Detroit Free Press folks have been calling the "the buy/sell question."
[The Tigers have] lost nine of their last 13 games and are four games out of the final wild-card spot in the American League.
A number of key Tigers, such as ace pitcher David Price and outfielder Yoenis Cespedes (cut and pasted that one from the article, thank you) are on the last year of their contract and would command a rather nice prospect or two from a team serious in making a run at the World Series this year. With a number of holes in their pitching staff and best-hitter-in-baseball Miguel Cabrera out for a few more weeks, a playoff run is somewhat iffy, so a half-empty view of things would lean towards the sell side if we have a Boolean buy/sell decision to make.
However, there is a third option to consider, especially for a former finance professor. If we make the players stocks, we also have a hold option, hanging on to the stock.
The analogy doesn't work all that well, since the players can go away in two months. However, if you trade a player now, he's gone and is unlikely to come back in free agency. It's a rare sight to see the object of a rent-a-player deal sign with the seller the next year, although I recall Jim Slaton do that in the late 70s, getting traded from Milwaukee to Detroit then going right back to the Brew Crew the next year as a free agent; that one hurt, since they were in the same division back then and Ben Oglivie (who went the other way in the trade) bloomed into a good power hitter on the other side of Lake Michigan.
So, if the Tigers were playing with the idea of trading David Price, a hidden cost of trading him would be losing the inside track of being his default value for next year. Pitchers like Price are rare; you can't just plunk down the going rate and get a Price 2.0 off the shelf.
That inside track option on Price or other quality free agents is something that gets underplayed in that buy/sell meme. That option could well be worth more than a good AA prospect or two.