When the New York Mets traded Tom Seaver to the Reds on June 15, 1977, Mets fans were so upset they tried to organize a boycott of home games until Seaver would return to Shea Stadium with the Reds in August.

The boycott never materialized, but the fans had a right to be upset. The four young players the Mets received for Seaver -- Steve Henderson, Pat Zachry, Doug Flynn and Dan Norman -- never developed into anything more than minor contributors and the Mets would average 97 losses in nonstrike seasons from 1977 to 1983.

The Seaver deal remains one of the most shocking deadline deals in baseball history. Even though everyone knew Seaver was at odds with Mets management over a new contract and the state of the team, nobody really expected the Mets to trade their franchise icon. That's what makes the trade deadline so exciting -- even if a big name is central to trade rumors, we don't know where the player will land.

The trade deadline was later moved from June 15 to July 31 in 1986, resulting in more deadline trades than occurred with the earlier date. Here are the five biggest blockbusters to happen in July -- not necessarily the best trades, but the ones with the biggest names in deals that sent shock waves through baseball land.

5. July 31, 1997: A's trade Mark McGwire to the Cardinals for Eric Ludwick, T.J. Mathews and Blake Stein.

Why the trade: The A's were floundering in the post-Bash Brothers era, Tony La Russa was already in St. Louis and McGwire was an impending free agent. The A's needed to rebuild and everyone knew they were shopping McGwire, but would they have the guts to trade him in a season in which he had a chance to break Roger Maris' home run record? Yes, they would. The surprising part was the destination: The Cardinals were 51-56 at the time of the trade, 7½ games out of first place and even further behind in the wild-card standings.

Quote: "What I hope is the fans understand we're trying to rebuild this team to a contending level and that sometimes calls for hard decisions." -- A's general manager Sandy Alderson

What happened: McGwire had 34 home runs for the A's but went on a tear with St. Louis, slamming 24 home runs in 51 games to finish with 58, three short of Maris' record. McGwire wouldn't test free agency but would instead sign a three-year deal with the Cards and break Maris' record the next year. The three pitchers the A's acquired never did much.

Similar player today: Let's see: Franchise icon, one of the game's premier power hitters maybe somebody like the Red Sox trading David Ortiz.

4. July 9, 2010: Mariners trade Cliff Lee and Mark Lowe to the Rangers for Justin Smoak, Blake Beavan, Josh Lueke and Matt Lawson.

Why the trade: Lee had won the AL Cy Young Award with the Indians in 2008 and then dominated in the 2009 postseason with the Phillies, going 4-0 in five starts with a 1.56 ERA. The Phillies inexplicably traded him to the Mariners that winter, but the Mariners were awful and Lee's ability and postseason performance made him the hot commodity on the trade market. The Rangers were in first place on July 9, but hadn't made the playoffs since 1999 and needed an ace to lead the rotation. The Mariners were close to a deal with the Yankees for Jesus Montero -- reports said Yankees GM Brian Cashman had actually called Lee to say a deal was imminent -- before the Rangers relented and finally included rookie first baseman Smoak. Mariners GM Jack Zduriencik didn't seem concerned about trading within the division.

Quote: "We had ongoing talks with several clubs. And at the end, when you're finished and you go another direction, before you consummate a deal, you always go back and tell the other club, 'Hey, look, this is the direction we're going, this is the decision we made.'" -- Zduriencik

What happened: Lee went only 4-6 down the stretch with the Rangers, but Texas won the division easily. Lee really earned his keep in the postseason, beating Tampa Bay twice in the division series and beating the Yankees with eight shutout innings in the ALCS. He did lose both his World Series starts, but the Rangers at least got there for the first time in franchise history. The transformation of the Rangers into one of the big players in MLB was helped by that World Series appearance -- helped by a division rival. As for the Mariners Smoak owns a .230 career average.

Similar player today: Cliff Lee?

3. July 31, 2004: In a four-team trade, the Red Sox trade Nomar Garciaparra to the Cubs and acquire Orlando Cabrera from the Expos and Doug Mientkiewicz from the Twins.

Why the trade: It's easy now to forget how popular Garciaparra was in Boston, winning batting titles in 1999 and 2000 and driving in 105 runs in 2003, when the Red Sox fell one game short of the World Series. But there were reports that Garciaparra was unhappy in Boston and the Red Sox had come close to an offseason deal that would have sent him to the Dodgers or White Sox and brought Alex Rodriguez to the Red Sox. General manager Theo Epstein was also interested in improving the team's defense, and Cabrera would be an upgrade there. Official news of the deal didn't come down until an hour after the deadline.

Quote: "I think as far as Nomar goes, maybe it was good. Give him some time to clear his head. Sometimes starting over is not so bad. He's going to a great place to play, just like Boston. Now what we need to do is get our team headed in the right direction and I think we have a good chance to do that." -- Red Sox manager Terry Francona

What happened: The Red Sox were 56-46 at the time of the trade, 8½ games behind the Yankees and a game out of the wild-card lead. They would go 42-18 after the trade and while they didn't catch the Yankees they would ride that momentum to a World Series crown. Cabrera hit .294, drove in 31 runs in 58 games and played excellent defense. The Cubs were 1½ games out of the wild card but would fall three games short of the playoffs. Garciaparra hit .297 with 20 RBIs in 43 games, missing some time with an injury (he'd never be completely healthy again).

Similar player today: Popular player, injury risk, impending free agent how about Chase Utley?

2. July 31, 2008: In a three-team deal, the Red Sox trade Manny Ramirez to the Dodgers and acquire Jason Bay from the Pirates.

Why the trade: The Red Sox were in second place behind the Rays, a game ahead of the Yankees and Twins in the wild-card race, but had grown tired of Manny's act, which had included a fight with teammate Kevin Youkilis, a physical altercation with the team's traveling secretary and, most damaging, several instances in late July of not running out ground balls, perhaps in protest of his contract situation. The Dodgers were 54-53, but just one game behind the Diamondbacks in the NL West. The Red Sox and Marlins were in heated talks, but Boston couldn't pry Class A slugger Mike Stanton away from the Marlins. The Pirates were then brought in, sending two-time All-Star Bay to Boston and receiving prospects Brandon Moss, Craig Hansen, Andy LaRoche and Bryan Morris from the Dodgers and Red Sox in a deal consummated at "3:59 and seconds," according to Pirates GM Neal Huntington (in other words, just before the 4 p.m. ET deadline).

Quote: "The Red Sox don't deserve a player like me. During my years here, I've seen how [the Red Sox] have mistreated other great players when they didn't want them to try to turn the fans against them. The Red Sox did the same with guys like Nomar Garciaparra and Pedro Martinez, and now they do the same with me. Their goal is to paint me as the bad guy. I love Boston fans, but the Red Sox don't deserve me. I'm not talking about money. Mental peace has no price, and I don't have peace here." -- Manny Ramirez, just before deadline day

What happened: Hitting .299/.398/.529 with Boston, Ramirez heated up with the Dodgers, hitting .411 in August and .396/.489/.743 over his two months with the team, carrying the Dodgers to the NL West title and finishing fourth in the MVP vote despite playing just 53 games in the National League. He also got the Dodgers to drop two team options for 2009 and 2010 (although he would end up re-signing with the club). The Dodgers upset the Cubs in the division series but lost to the Phillies in the NLCS. Bay played well with the Red Sox, who lost Game 7 of the ALCS, and hit 36 home runs the following season. As for the Pirates well, LaRoche was the big prospect but didn't pan out and only Morris still remains with the organization.

Similar player today: Veteran slugger who had fallen from grace sounds sort of like Alex Rodriguez, if A-Rod were healthy and hitting.

1. July 31, 1998: Mariners trade Randy Johnson to the Astros for Freddy Garcia, Carlos Guillen and John Halama.

Why the trade: The Mariners had won the division title in 1997 but hadn't signed Johnson, an impending free agent who had made it clear he wasn't returning to Seattle. They first shopped him around in the offseason, reportedly turning down a Mariano Rivera offer from the Yankees because a "Mariner official also said there are concerns about Rivera's arm. There were suspicions the 27-year-old right-hander had shoulder trouble late in the season."

Anyway, the Astros were in first place but looking for another starter to complement Mike Hampton, Shane Reynolds and Jose Lima.

Quote: "It's hard to believe, but there was very little interest in Randy Johnson." -- Mariners general manager Woody Woodward. Really, Woody?

What happened: The trade was widely panned, especially in Seattle, where Ken Griffey Jr. said "I was ordered not to say anything." In Houston, manager Larry Dierker seemed critical, as well, suggesting the team was sacrificing the future for the present. Well, Johnson was dominant for the Astros, going 10-1 with a 1.28 ERA in 11 starts, but the Astros would lose in the division series to the Padres. Garcia would be better than advertised (the Mariners had wanted Scott Elarton) and he, Guillen and Halama would help the Mariners to the playoffs in 2000 and 2001.

Similar player today: Imagine a taller Clayton Kershaw with longer hair and a harder fastball and meaner scowl. In other words, the best lefty in the game.

Honorable mention: David Cone to the Yankees (1995); CC Sabathia to the Brewers (2008); Fred McGriff to the Braves (1993); Curt Schilling to the Diamondbacks (2000); Mark Teixeira to the Braves (2007); Scott Rolen to the Cardinals (2002).