It's an old baseball offseason axiom: There is no such thing as a bad one-year contract. The idea makes sense. You can't cripple your franchise all that badly with a one-year deal. Even if the player is terrible, they're gone in a year.
Of course, you can't build a franchise on one-year contracts either. If a player outplays his contract, you'll probably have to overpay to keep him from heading somewhere else. They are short-term fixes.
Think of one-year baseball contracts like a college team bringing in a graduate transfer. They can be a useful supplement, but you better have a larger plan in place.
But not all one-year contracts are created equal, particularly after this past offseason's historically stagnant free-agent market. Of all the free agents heading into 2018, 15 received a contract of three years or longer. Just 34 signed a two-year deal. That means everybody else just grabbed a one-year deal. Some of these have paid off handsomely. Some have been the equivalent of placing a giant pile of money in center field and setting in on fire. But with just over a month and a half left in the season, we can get a sense of which of these turned out exactly as the teams that signed them might have hoped -- and which turned out the opposite of that.
Success stories
Matt Adams, Washington Nationals, $4 million
Quietly, very quietly, Adams has put together the best season of his career. He's two homers shy of tying a career-high 20, and he his .351 OBP is higher than teammates Anthony Rendon (.341), Trea Turner (.341) and Ryan Zimmerman (.321). Adams' .899 OPS is higher than Rhys Hoskins (.883), Joey Votto (.853) and Kristopher Bryant (.854). Here's to betting Adams gets a longer deal just than one year this offseason.

Jonathan Lucroy, Oakland A's, $6.5 million
Lucroy was a National League MVP Award candidate just four years ago with the Brewers, so the A's were widely praised for taking a chance on him this offseason. While they haven't gotten the production from his bat they might have hoped for (though he has heated up of late), he has been invaluable behind the plate, particularly with a young, oft-injured pitching staff. The A's are perhaps the biggest happy surprise of the first two-thirds of this season, and Lucroy -- both on and off the field -- is a big reason why.
Mike Moustakas, Kansas City Royals, $5.5 million
Moustakas had a perfectly respectable season for the Royals -- .249/.309/.468, essentially his career average for that team -- but the real value for Kansas City was what he brought back when the Royals traded him to the Brewers: outfielder Brett Phillips, a classic post-hype sleeper who is exactly the sort of player the Royals need to try to bring in to try to help them in what will be a long climb back to respectability. You bring in Moustakas back for precisely this purpose: to flip him at the non-waiver Trade Deadline for future help. How Phillips will turn out is still up in the air, but the concept is the right one.

Carsten Sabathia, New York Yankees, $10 million
Did you realize that this has been Sabathia's best year since he was last an All-Star in 2012? His 3.49 ERA is down nearly two runs since 2014, and he just struck out 12 White Sox hitters in 5 2/3 innings on Tuesday. Sabathia turned 38 years old last month, but he's remained as stubbornly durable as he's always been. Sabathia wants to come back next year, and at this point, both sides would probably be perfectly happy with the same deal they just signed.
Bud Norris, St. Louis Cardinals, $3 million
The Cardinals' bullpen has been a disaster for most of this season, but its one stabilizing force has been Norris, who took over the closer job from Greg Holland in the season's opening week and has held onto it ever since. Norris never had a save before last season. He now has 41 in two years. The Cards didn't trade Norris at the Deadline like many thought they would, and he's now the constant in a bullpen that has been reconstructed, and much improved, in the past fortnight.
Biggest disappointments
Greg Holland, St. Louis Cardinals, $14 million
Holland was always an odd fit for the Cardinals, who had already supplemented their bullpen with veterans like Norris and Luke Gregerson, and had just promoted flamethrowing rookie Jordan Hicks to the Opening Day roster. But former manager Mike Matheny wanted a proven closer, and Holland proved to be a total disaster, walking 22 batters in 25 innings and putting up a 7.62 ERA. A year after leading the National League with 41 saves, he had zero for St. Louis. The Cards ended up waiving Holland outright, and in his first appearance for Washington on Tuesday afternoon, he struck out the side. Go figure.

Jaime Garcia, Toronto Blue Jays, $10 million
The Blue Jays were still dreaming they might be contenders when they brought in the veteran Garcia, and the Jays won the left-hander's first three starts. It has been a nightmare since, though, with Garcia putting up the worst walk (11.7 percent) and home run (1.70 per nine innings) rates of his career. After landing on the disabled list in June with left shoulder inflammation, Garcia returned to the bullpen, where he hasn't been much better. His last appearance was on July 30 in Oakland, in which he gave up six runs in 1 1/3 innings. It was the seventh straight loss for Toronto in games Garcia has pitched, and his ERA is now 6.42. 
Logan Morrison, Minnesota Twins, $5.5 million
Remember when this was the best deal of the offseason? Morrison thought his breakout year in 2017 would lead to a massive pay day, but it didn't work out that way. Skepticism by clubs turned out to be wise: Morrison has had the worst year of his career, hitting .190/.282/.370, and the Twins are likely to buy out his $1 million option this offseason.
Colby Rasmus, Baltimore Orioles, $3 million
While most observers were focused on Chris Davis' nightmare season, Rasmus, sort of amazingly, was even worse. Rasmus made 49 plate appearances for the Orioles. He had six hits, three walks, 19 strikeouts and 10 total bases. Rasmus' line in those 49 plate appearances: .133/.204/.222. He had has many errors as extra base hits (one). On July 3, he left his team in the middle of the season … for the second year in a row. 
Jose Reyes, New York Mets, $2 million
It has been a little baffling why the Mets have insisted on keeping the 35-year-old Reyes on their roster. His bat has evaporated; he's hitting .186/.257/.281 with 10 extra-base hits in 183 plate appearances. Reyes has a negative WAR rating (minus-0.6) for the second consecutive season. And that's only if you ignore his pitching appearance (one inning, six runs, two homers), which was so bad it cost him another 0.2 WAR. And he still wants to come back next year!