MLB Trades: The 6 Best Deadline Deals Ever

July 31st is always an exciting day in the world of sports. As the Major League Baseball season enters its final full month, it also puts an end to trading for that season. 

Leading up to the last day in July, the sports media world is always in a frenzy with all the trades that are going down. Some of these are foreseen, yet some others are out of the blue. 

Either way, people always wonder how the deal will pay off. Here are six trades that may not have seemed too smart or significant at the time, but ended up paying off big time for some MLB franchises. 

6. Mike Lowell to the Florida Marlins

Many fans and critics didn't know what the Florida Marlins were thinking, trading Ed Yarnall, Todd Noel and Mark Johnson for a young third baseman named Mike Lowell. 

Lowell, who only played eight major league games for the New York Yankees before making the move to Florida, established himself as one of the league's best third basemen and became a three-time All-Star. 

Ed Yarnall, Todd Noel and Mark Johnson made almost no impact during their brief careers. 

5. Derek Lowe and Jason Varitek to the Boston Red Sox

This is a no-brainer. The Boston Red Sox traded relief pitcher Heathcliff Slocumb to the Seattle Mariners for two young players, pitcher Derek Lowe and catcher Jason Varitek. 

Aside from having a fantastic name, Heathcliff Slocumb never produced much for the Mariners. 

Lowe was a two-time All-Star selection in Boston and helped them win a World Series in 2004, while Varitek has been the face of the franchise since being traded there. He is a clubhouse leader and one of the most respected, successful and consistent players in the game. 

4. Luis Gonzalez to the Arizona Diamondbacks

In 1998, the Arizona Diamondbacks shipped off outfielder Karim Garcia, who had been moderately successful for the then-young franchise, for veteran Luis Gonzalez. 

Gonzalez at the time had been a relative disappointment for the Detroit Tigers. He liked something about the desert air however; in his first full year in Arizona, he hit .336. 

Gonzalez ended up being a five-time All-Star and helped Arizona beat the New York Yankees in the 2001 World Series. 

3. Mark McGwire to the St. Louis Cardinals

Nothing really needs to be said here that isn't already known. The Oakland Athletics received three pitchers—T.J. Matthews, Eric Ludwick and Blake Stein—in exchange for Mark McGwire. 

Unlike some of the other trades on this list, McGwire was far from unknown at the time this trade went down in 1997. He was quite the opposite actually, already being named an All-Star six times. 

McGwire's contract was going to end and he didn't want to stay in Oakland, but you still have to wonder that the A's should have tried harder to keep the slugger. The home run race that ensued between McGwire and Sammy Sosa in 1998 was one of the most exciting races in sports history, and McGwire will forever be remembered as a St. Louis Cardinal, not an Oakland Athletic. 

2. Pedro Martinez to the Boston Red Sox

This trade succeeded another lopsided trade involving Pedro Martinez, when the Los Angeles Dodgers traded a young Martinez to the Montreal Expos for Delino DeShields. 

In 1997, after winning the Cy Young Award, the Expos traded Pedro to the Boston Red Sox for Carl Pavano and Tony Armas Jr. 

I list this trade worse than the former because Pedro will be forever remembered as a Red Sox. He won two more Cy Young Awards there and was instrumental in Boston's 2004 World Series win. 

1. Jeff Bagwell to the Houston Astros

Whenever the discussion comes up about the worst trades in sports history, this infamous trade is never absent from the conversation. 

The Boston Red Sox traded the young Bagwell for relief pitcher Larry Andersen. 

Andersen was a major bust for the Red Sox, pitching only one season after the trade took place. 

Bagwell, however, became a major star for the Houston Astros and one of the best outfielders of his era. Bagwell hit 449 home runs and over 1,500 RBI in his 15-year career, and is now a legend in Houston. 

He would probably still be the best player for the Astros!