For all of the instant and occasionally breathless analysis of actual and potential trades that occurs at this time of year, it is important to acknowledge that even when such deals are consummated, their impact tends to be overstated. That doesn't mean that contenders are wrong to shore up glaring weaknesses that threaten to derail them, or bank upon proven veterans recovering his lost productivity with a change of scenery. Both concepts are sound; a contending team shouldn't tolerate replacement level production because so many slightly better options abound, and given the chance, even established players who are struggling are more likely to approximate their career norms barring injury or advanced age. Even so, the instances where the addition of a single player or set of players around the trade deadline make the difference between making the playoffs and sitting at home are much less common than one would expect.
As last year's deadline approached, my Baseball Prospectus colleague Colin Wyers undertook a study of deadline deals in the Wild Card era (1995 through 2010, given that the 2011 season hadn't ended) and found that of 180 deals made nearing the deadline, just 10 produced enough of an impact — enough value in terms of Wins Above Replacement Player — to be the difference between making or missing the playoffs. That is to say, the value of a player or players acquired in terms of WARP was greater than the slim margin by which a team reached the postseason. A quick glance at last year's deals suggests an addition to the list, one that can illustrate the concept. From the July 27 trade that sent Colby Rasmus and three other players to Toronto, St. Louis received pitchers Edwin Jackson, Octavio Dotel and Mark Rzepczynski plus Corey Patterson, and on July 31 the Cardinals sent minor leaguer Alex Castellanos to the Dodgers for shortstop Rafael Furcal. Those imported players brought St. Louis an additional 2.4 WARP and the Cardinals won the Wild Card by a mere game on the final day of the regular season.
Why do so few trades fit the bill? First, it's important to remember that even over the course of 17 seasons, there simply aren't an overwhelming number instances where a playoff spot is decided by a close margin. According to research by Baseball Prospectus' Dan Turkenkopf, of the 102 division titles won during the Wild Card era, 33 (32.4 percent) have been decided by three games or fewer, about two per year. Five ended in a tie that have been decided by tiebreaker with the "loser" taking the Wild Card, 13 have been decided by one game (including play-in tiebreakers), 12 by two games and six by three games. Of the one-, two-, and three-game margins, 11 of the teams on the short end still won the Wild Card, meaning that in many cases, the margin for the division winners between continuing and taking an October vacation was actually larger than three games. The Wild Card itself is more hotly contested; of the 34 winners, 19 (55.9 percent) have been decided by three or fewer games: 12 by one game, three by two games, and four by three games.
Beyond that, BP's formulation of the value metric sets a higher replacement level than those of Baseball-Reference or FanGraphs, and is particularly stingy when it comes to pitching valuations via the adjustments it makes for bullpen and defensive support. A merely average full-time player might produce 2.0 WARP in a season, or roughly 0.67 over the final two months of the season, and likewise for a starting pitcher, while relievers may wind up accumulating even smaller fractions. The use of replacement level in such calculations may blur the accounting somewhat; it serves as a generic stand-in for a team's minor league or free talent alternatives, when in fact a team might have actually been receiving sub-replacement level production. Even so, in most cases, it works just fine. Returning to the Ryan Dempster example I gave last week, Dempster has produced 1.6 WARP, and could be expected to produce about 0.8 more just going by that current pace, while Nathan Eovaldi, since traded from the Dodgers to the Marlins, had produced −0.1 WARP, close enough to replacement level to call a wash. In order for a Dempster deal to qualify as a difference-maker under this methodology, he'd have to raise his level of performance to at least 1.0 WARP the rest of the way on a team that just makes the playoffs by the skin of its teeth.
What follows is a look at the only six deadline deals (or sets of deals) in the Wild Card Era that added at least 2.0 WARP and provided the margin between a playoff spot and staying home. Note that because WARP undergoes tweaks in its underlying methodology from time to time, the actual numbers may have shifted slightly in the year since Wyers' article was published, particularly on the pitching side.
1. 2008 Dodgers, 5.0 WARP: Manny Ramirez 4.2, Casey Blake 0.8
Margin: Won NL West by 2 games
Traded on July 31 as part of a shocking three-way, six-player deal between the Red Sox, Pirates and Dodgers, Ramirez famously took to Dodger blue, bumping light-hitting Juan Pierre to the bench, hitting .396/.489/.743 with 17 homers in 53 games and producing enough WARP to lead the team for the entire season. Blake, who arrived from the Indians via a July 26 deal that cost the Dodgers catching prospect Carlos Santana, replaced Blake DeWitt and Andy LaRoche at third base and hit .251/.313/.460 with 10 homers the rest of the way. The Dodgers were 54-53 at the time the Ramirez deal was made; they lost that night before he could arrive to fall two games back in the division, but went 30-24 the rest of the way to edge the Diamondbacks.
Margin: Won NL Wild Card by 1 game
The Brewers got a head start on the trading deadline, acquiring the previous year's AL Cy Young winner from the Indians in exchange for a four-player package on July 7. They had the third-best record in the league, but at 49-40, were also running third in the NL Central, one game behind the Cardinals. Striking early provided a huge gain, as Sabathia was able to start three of the Brewers' next seven games, including the two on either side of the All-Star break. He was dominant, going 11-2 with a 1.65 ERA while averaging 7.7 innings per start over 17 starts, and carried the team on his oversized back down the stretch by making his final three starts of the season — three of the Brewers' final eight games — on three days' rest. The last of them was a a one-run complete game on the final day of the season against the Cubs that clinched the team's first playoff berth since 1982. Durham, acquired from the Giants for two minor leaguers on July 25, shared time at second base with a struggling Rickie Weeks and hit .280/.369/.477 in the final stretch of his 14-year big league career.
3. 2003 Cubs, 3.3 WARP: Aramis Ramirez 2.0, Kenny Lofton 1.6, Doug Glanville −0.3
Margin: Won NL Central by 1 game
Just 50-50 and 5 1/2 games back in the NL Central on July 23, the Cubs traded three players to the Pirates in exchange for Ramirez (who was growing too expensive) and Lofton (whom they had signed over the winter with the intention of flipping). Ramirez took over third base, where the Cubs had shuffled through four different players, and hit .259/.314/.491 with 15 homers in 63 games the rest of the way. Lofton took over centerfield, where Corey Patterson had suffered a season-ending ACL tear a couple of weeks earlier; he also bumped Mark Grudzielanek out of the leadoff spot, and hit a sizzling .327/.381/.471 with 12 steals in 56 games down the stretch. With those two on the roster, the team went 38-24 the rest of the way, including 19-8 in September. Glanville, who was obtained as further outfield insurance on July 30 in a deal with the Rangers, played sparingly after the trade, hitting .235/.259/.294 in 55 plate appearances.
4. 1997 Giants, 2.9 WARP: Brian Johnson 1.4, Danny Darwin 0.6, Roberto Hernandez 0.6, Wilson Alvarez 0.3
Margin: Won NL West by 2 games
Between July 16 and July 31, the Giants pulled off four separate trades. Two of them (Pat Rapp from the Marlins and Cory Bailey from the Rangers) produced zero WARP from pitchers who didn't last long, but the other two paid significant dividends. Johnson, a backup catcher for the Tigers, was acquired on July 16, when the Giants were 53-41 and leading the division by three games. He replaced light-hitting Rick Wilkins as the team's regular catcher and hit .279/.333/.525 with 11 homers in 56 games down the stretch. His 12th-inning game-winning homer against the Dodgers on September 18 moved the two teams into a tie for first place in their final meeting of the season; the Giants would hold onto the top spot the rest of the way and finish 90-72. Pitchers Alvarez, Darwin and Hernandez were acquired as part of the infamous nine-player "White Flag" deal with the White Sox, who were just three games out of first place at the time. They provided bulk innings down the stretch, but weren't tremendously effective. Alvarez put up a 4.48 ERA in 11 starts and 66 1/3 innings — 4.20 was the league average — Darwin a 4.91 ERA in 10 appearances (seven starts) and 44 1/3 innings, and Hernandez posted a 2.48 ERA in 32 2/3 innings out of the bullpen, notching four saves.
5. 2011 Cardinals, 2.4 WARP: Rafael Furcal 1.4, Edwin Jackson 0.8, Octavio Dotel 0.4, Mark Rzepczynski 0.2, Corey Patterson -0.4
Margin: Won NL Wild Card by 1 game
The Cardinals were 55-48 on July 26, leading the NL Central by half a game when they sent the enigmatic Rasmus and three other players to Toronto. Jackson put up a 3.58 ERA in 13 appearances (12 starts) down the stretch, while the righty Dotel (3.28 ERA in 24.2 innings) and the lefty Rzepczynski (3.97 ERA in 22 2/3 innings) gave manager Tony La Russa a pair of specialists who both struck out more than 11 men per nine. Furcal, who had been limited to 37 games and a .197/.272/.248 line with the Dodgers due to thumb and oblique injuries, returned to form at least somewhat, hitting .255/.316/.418 in 50 games for the Cardinals and replacing Ryan Theriot at shortstop. Unlike all of the hauls mentioned here, this one helped their team capture a world championship, via a thrilling seven-game World Series win over the Rangers.
6. 1999 Mets, 2.2 WARP: Darryl Hamilton 1.1, Kenny Rogers 0.7, Shawon Dunston 0.2, Chuck McElroy 0.1, Billy Taylor 0.1
Margin: Won NL Wild Card by 1 game, via play-in tiebreakerRockies Reds Braves