MLB Trades 2017: Dissecting Top Deals Made Heading Towards Deadline

The July 31 trade deadline is vital for any of the teams that view themselves as contenders, as it represents a key opportunity to upgrade the team prior to the stretch run.

It demonstrates to players and fans that the team's management is serious about capitalizing on the chances of getting to the playoffs and potentially winning the World Series.

With the deadline just days away, a number of deals have already taken place this summer. The defending World Series champions Chicago Cubs got things started when they completed a notable deal with rivals Chicago White Sox for starting pitcher Jose Quintana.

The Cubs acquired the starter on July 14 for prospects outfielder Eloy Jimenez, pitcher Dylan Cease, first baseman Matt Rose and infielder Bryant Flete. None of those prospects have reached the big leagues, as the White Sox are looking to build up their roster of young talent so the team can be competitive in future years.

The left-handed Quintana has gotten off to a sharp start with his new team, as he is 2-0 with a 2.08 earned-run average and 19 strikeouts in 13 innings. The arrival of Quintana coincided with improved play by the team, which had underperformed through the All-Star break. 

Quintana had struggled with the White Sox during the first half of the year, but he is known for his consistency and ability to give his team a chance to win. He has career marks of a 3.50 ERA and a 1.244 WHIP.

The Washington Nationals have been a first-place team in the National League East, and much of their success has come as a result of their dynamic offense and strong starting pitching. Their bullpen has been close to a disaster area, as the Nats have blown leads since the start of the season.

Ross D. Franklin/Associated Press

Manager Dusty Baker finally got some relief July 16 when the Nats acquired Sean Doolittle and Ryan Madson from the Oakland A's for Blake Treinen and a pair of prospects.

The left-handed Doolittle pitched well for Oakland with a 3.38 ERA and a 0.656 WHIP in 21.1 innings, but he has gotten off to a poor start in Washington. Doolittle has a 9.00 ERA in his first four appearances.

Madson has not allowed an earned run in his first four appearances, and he has five strikeouts in 4.0 innings of work.

The Arizona Diamondbacks are one of the big stories in the National League this year, as they are in the top wild-card position in the National League as they approach the final two months of the season.

The Diamondbacks upgraded their offense when they traded for outfielder J.D. Martinez of the Detroit Tigers for Dawel Lugo, Sergio Alcantara and Jose King.

Martinez had a .305/.388/.630 slash line with the Tigers along with 16 home runs and 39 runs batted in. He has already hit three home runs in his first five games with the Diamondbacks, and he could prove to be a difference maker as the season approaches the stretch run. 

The New York Yankees and the White Sox completed a blockbuster trade July 18 when the Bronx Bombers acquired power-hitting third baseman Todd Frazier and relief pitcher David Robertson for relief pitcher Tyler Clippard and three minor-leaguers, pitcher Ian Clarkin, outfielder Blake Rutherford and outfielder Tito Polo.

Since the White Sox are fully rebuilding while sitting in last place in the AL Central, they had little need for Frazier and Robertson. The Yankees are chasing the Boston Red Sox for first place in the American League East and clearly needed an upgrade.

Frazier has hit 17 home runs this season, and all but one of them were hit with the White Sox. Robertson pitched for the Yankees from 2008 through 2014, and he has a 2.25 ERA in his first four appearances in his return to the team.

The Red Sox were thought to be contenders in the Frazier deal, but they did not outbid the Yankees. They have struggled at the third base position all season, and they acquired Eduardo Nunez from the San Francisco Giants on Tuesday.

Nunez is primarily a third baseman, but he can also play shortstop. Nunez has a .308/.334/.417 slash line with the Giants along with four home runs and 31 RBI. The Red Sox have a day off Thursday before returning to action Friday at home against the Kansas City Royals, and Nunez is expected to be in uniform and in the lineup.

The Red Sox sent minor-league pitching prospects Shaun Anderson and Gregory Santos to the Giants to complete the deal. 

The Colorado Rockies are chasing the Diamondbacks for second place in the National League West, and they are currently in the No. 2 wild-card position. They made a move to bolster their bullpen Wednesday when they acquired Pat Neshek from the Philadelphia Phillies for three minor-league prospects in Jose Gomez, Alejandro Requena and J.D. Hammer.

Neshek made the National League All-Star team this year, and he has a 1.12 ERA along with a 0.818 WHIP. 

The 36-year-old pitcher has an awkward delivery that often makes it tough on hitters, and he is the kind of relief pitcher who has been able to come in and give the Phillies an inning of shutdown relief. The Rockies are clearly looking for the same level of success from Neshek.