Unlike baseball's planned premier events, such as the World Series or the All-Star Game, the trade deadline wasn't envisioned as one of baseball's most significant seasonal moments.
Baseball's first MLB-wide trade deadline was instituted for the 1923 season, to standardize the differing deadlines that the American League and National League had instituted. Simultaneously the result of a war between commissioner Judge Kenesaw Mountain Landis and AL president Ban Johnson and between Cardinals owner Branch Rickey and the owners of the New York teams (among other feuds), the June 15 trade deadline stayed in force for generations. But it was never a Very Big Moment in baseball's season ... until 1986, when baseball moved to a July 31 deadline, which stayed in effect until the very-recent-but-slight change to Aug. 1.
As it turned out, July 31 turned out to be a fairly elegant date for the non-waiver trade deadline; it was late enough in the season that more teams are throwing in the towel than in mid-June, but late enough that players can have a real effect on the pennant races. Combine that with free agency -- meaning teams falling from contention would frequently have "move 'em or lose 'em" players -- and you have one of baseball's most exciting in-season times.
As might be expected, with only two months of playing time for a player acquired right at the deadline, the list of best trade adds isn't just made up of superstars. Some decidedly non-superstars turned out to be key pennant race adds too. Before we get to the projections for this year's best realistic trade additions at the deadline -- there is no Mike Trout projection listed below -- let's look at some of the most valuable adds of the July deadline era, ranked by FanGraphs WAR (fWAR) and listed with the team that acquired him.
1. CC Sabathia, 2008 Brewers (4.6 fWAR): Sabathia went 11-2 with a microscopic 1.65 ERA in 17 starts for the Brewers. None of the principals initially dealt to the Indians to get him -- Matt LaPorta, Zach Jackson and Rob Bryson -- panned out, though the player to be named, Michael Brantley, formed a key part of a future Indians core.
2. Randy Winn, 2005 Giants (3.6 fWAR): One thing you don't expect to see very often is a best-of list featuring Randy Winn near the top. But his last name proves to be accurate here; the Giants acquired him to shore up a center-field position that had been manned by a done Marquis Grissom and a never-started Jason Ellison. This was not a traditional addition, given that the Giants were below .500, but so was every other team in the NL West (in a division the Padres won by going 82-80 while the Giants finished 75-87). Winn hit 14 homers in two months for the Giants; he never hit more than 14 in any other season.
3. Mark Teixeira, 2008 Angels (3.5 fWAR): This was the second consecutive year Teixeira was traded at the deadline; the previous year, a 2007 trade to the Braves, would have made the top 25 if this list went that deep. Replacing Casey Kotchman (who went to Atlanta), Teixeira hit .358/.449/.632 for the Angels. While the Halos were eliminated quickly by the Red Sox in the playoffs, that was hardly the fault of Tex, who hit .467 in his first playoff appearance. Neither Kotchman nor Stephen Marek made the Angels have second thoughts later, unlike the Braves, who traded Elvis Andrus, Matt Harrison, Neftali Feliz and Jarrod Saltalamacchia for Teixeira just a year earlier.
4. Randy Johnson, 1998 Astros (3.3 fWAR): This turned out to be the ultimate win-win deadline trade: The Astros got a pitcher who went 10-1 with a 1.28 ERA in 11 starts and the Mariners got Carlos Guillen, Freddy Garcia and John Halama, key parts of the Mariners' core in later years. Well, the first two at least, though Halama had his moments.
5. Fred McGriff, 1993 Braves (3.1 fWAR): While the Sid Bream/Brian Hunter combo had its moments at the start of the 1990s Braves dynasty, it couldn't come close to matching the late prime years of the Crime Dog. McGriff didn't disappoint, hitting .310/.392/.612 for the Braves.
6. Manny Ramirez, 2008 Dodgers (3.0 fWAR): Manny Being Manny was sometimes a really good thing. Ramirez was still one of the elite hitters in baseball well into his mid-30s. Neither Andy LaRoche nor Bryan Morris made the Dodgers regret the trade. But even if those two players had Manny's .396/.489/.743 line (and a 221 OPS+), the Dodgers wouldn't have cared too much. They won the division by only two games.
7. Scott Rolen, 2002 Cardinals (3.0 fWAR): Rolen is one of the most underrated players of his generation -- if not the most underrated. Rarely did his star shine as brightly as it did in his early Cardinals performances. The Cards didn't end up really needing Rolen to win the division, something they managed in a walk, and Rolen's shoulder ended his postseason early, but he gave a big boost to a team that was still reeling from Darryl Kile's tragic death in June.
8. Chase Headley, 2014 Yankees (2.8 fWAR): Perhaps this move doesn't jump out in your head, but Headley was still a Gold Glove third baseman at this point in his career and played spectacular defense down the stretch, and his 119 OPS+ made him an excellent pickup.
9. Yoenis Cespedes, 2015 Mets (2.7 fWAR): Hitting .287/.337/.604 for the Mets with 17 homers in just 57 games, Cespedes provided a massive boost for an offense that hit just .233/.298/.363 in the first half. After the Mets made the World Series, if the team hadn't been able sign Cespedes, the scene in Queens would have looked like one of those clips with pitchfork-waving villagers from a 1930s Frankenstein movie.
The rest of the top 15:
10. David Price (2.7 fWAR), 2015 Blue Jays; 11. Curt Schilling (2.7 fWAR), 2000 Diamondbacks; 12. Matt Holliday (2.6 fWAR), 2009 Cardinals; 13. Randy Velarde (2.5 fWAR), 1999 Athletics; 14. Doyle Alexander (2.5 fWAR), 1987 Tigers; 15. Shannon Stewart (2.4 fWAR), 2003 Twins.
What that list tells us is that you could add two to four wins by trading for the right player at the deadline. Who could deliver that kind of upside in 2017? The players below strike me as having at least a realistic chance of being traded, ranked by their expected two-month fWAR, with their calculated likelihood for delivering at least 2.0 fWAR (and the two players with a greater than 1 percent shot at providing 3.0 or more fWAR) in the last two months of the season.
1. Josh Donaldson, Toronto Blue Jays (44.1 percent chance of 2.0-plus fWAR; 5.1 percent of 3.0-plus): He is one of the least likely players on this list to get traded, but while the Blue Jays have played much better baseball since their wretched start, it's not that difficult to envision a scenario in which they fall out of the playoff hunt and start to wonder a bit about what they could land for Donaldson, who will be a 32-year-old free agent after the 2018 season.
2. Chris Archer, Tampa Bay Rays (19.4 percent chance of 2.0-plus fWAR, 1.1 percent of 3.0-plus): The Rays are under no immediate pressure to trade Archer, with reasonable club options under contract until 2021. But Tampa Bay never calls players hands off, and if the Rays are just shuffling around .500, I can totally see them being willing to let Archer go in the right blockbuster. This team, after all, has several pitching prospects nearly ready to contribute in the majors.
3. Andrew McCutchen, Pittsburgh Pirates (13.2 percent of 2.0-plus fWAR): The Pirates have been insistent that they're not looking to rebuild at this point, but with McCutchen playing like McCutchen again -- at least offensively -- this trade deadline looks like the best opportunity for the Pirates to get something for him while the getting is good. The team is unlikely, after all, to keep Austin Meadows in the minors for the 2018 season, and the claiming a wild card in the National League is looking harder than winning the NL Central.
4. Jose Quintana, Chicago White Sox (9.3 percent chance of 2.0-plus fWAR): Quintana is not pitching as poorly as his ERA indicates, with a FIP around three-quarters of a run better, and he hasn't had a long-term tendency to underperform his peripheral numbers. There's little question that the White Sox would get less for Quintana now than they would have this past winter, but in the event that they decide to take a package, he's still likely to be a solid pitcher down the stretch. The contract makes him more valuable, but we're just looking at straight-up 2017 wins here.
5. Christian Yelich, Miami Marlins (5.8 percent chance of 2.0-plus fWAR): Yelich's numbers aren't as flashy as teammate Marcell Ozuna's, but the projections still prefer Yelich, who has proved to be a solid full-time defensive center fielder, and I still think he has a batting title in him at some point given what an elite line-drive machine he is when he's on.
6. Brian Dozier, Minnesota Twins (3.5 percent chance of 2.0-plus fWAR): The White Sox with Quintana aren't the only AL Central team to discover that assets you hold sometimes decline in value. Don't get me wrong, Dozier is having a solid 2017, but he's not playing like the crazy home run machine he was in 2016. The Twins could still move Dozier, but they'd be even less successful prying away a top-50 prospect than they were in their offseason bid to trade Dozier to the Dodgers, who instead acquired Logan Forsythe (who hasn't really worked out, of course).
7. Lorenzo Cain, Kansas City Royals (3.3 percent chance of 2.0-plus fWAR): When push comes to shove, I think the Royals will be resistant to trading as many players as they should, even if they drop out of the race. The team has played well in June, so there's no chance Cain will be traded now, but Kansas City's success is precarious, given how reliant the pitching staff has been on Jason Vargas pitching like Greg Maddux.
8. Ian Kinsler, Detroit Tigers (3.3 percent chance of 2.0-plus fWAR): He was the subject of a few trade rumors this past offseason. The Tigers are aware that they're at the end of a success cycle, and the current core may not be good enough to be a serious playoff contender. If the next good Tigers team isn't playing in 2017 or 2018, it doesn't make a lot of sense to hang on to Kinsler, as terrific as he has been.
9. Johnny Cueto, San Francisco Giants (2.5 percent chance of 2.0-plus fWAR): If Cueto were guaranteed to come back in 2018, I think the Giants would hold off on trading him. But given the uncertainty because of his opt-out and the team's hole, dug so deep that there's almost no realistic hope of a 2017 comeback, the team has to be serious about fielding offers.
10. Justin Verlander, Detroit Tigers (2.1 percent chance of 2.0-plus fWAR): Verlander's remaining contract length at the trade deadline, which will essentially be for two months plus two years beyond and $65 million, complicates the team's chances of landing top prospects in return for their fading ace. Also complicating things: His walk rate has nearly doubled this year compared with 2016, plus a 4.20 FIP, his worst in a decade. Still, he is one year from a Cy Young silver, and he has a reputation as a durable innings-eater and as someone you'd like to see starting a playoff game, so there will be at least some interest in acquiring him if the numbers are right.