The major league trade deadline is Monday, Aug. 1, and contenders around the league are bolstering their rosters.

As October approaches, here is a look back at some of the notable deals made in recent years by eventual World Series champions.

2010 San Francisco Giants

Acquired Javier Lopez from Pirates

The Giants' bullpen wasn’t a problem, but Lopez made it better. Before the deadline, San Francisco had a 3.37 ERA, seventh in the majors. But from Aug. 1 on, they had a major league-best 2.37 ERA. With Lopez on the team, lefties hit .212 off the bullpen; they had hit .251 prior.

The lefty specialist came in handy in the postseason, too. With the tying run on second base in a one-run game in Game 4 of the NLDS, Lopez struck out Jason Heyward swinging to end the threat. In the NLCS, Lopez faced Ryan Howard five times and allowed just one hit, which came with the bases empty. In Game 2 of the World Series, Lopez induced a flyout from Josh Hamilton with a runner in scoring position in a two-run game.

2011 St. Louis Cardinals

Acquired Marc Rzepczynski from Blue Jays

The Cardinals traded for four Blue Jays players on July 27, 2011, as well as Rafael Furcal from the Dodgers on July 31, but Rzepczynski arguably made the biggest impact in the postseason. He pitched 7 1/3 innings in the NLCS and World Series, allowing one run while striking out eight. With St. Louis on the brink of elimination and down three runs in the top of the eighth inning in the World Series, Rzepczynski induced three ground outs on eight pitches. The Cardinals went on to score one run in the eighth and two in the ninth before David Freese's walk-off home run in the 11th.

2012 Giants

Acquired Hunter Pence from Phillies and Marco Scutaro from Rockies

The Giants had been starting Nate Schierholtz in right field and needed an everyday player in that spot. They were batting .230 with runners in scoring position, 28th in the majors. Pence only hit .219 for the Giants the rest of the season, but he hit .273 with runners in scoring position. The team had gone 56-47, tied for the ninth-best record in baseball, through July 31; San Francisco went 38-21 the rest of the way, the best record in the National League. Pence was noted during the 2012 postseason for his pregame speeches as the Giants faced three elimination games in each of the first two rounds of the playoffs.

Scutaro was hitting .271 with the Rockies, but he went on to hit .362 in his short time with the Giants. Scutaro was the 2012 NLCS MVP after hitting .500 during the series. He also had two multi-hit games in the World Series.

Marco Scutaro batted .355 in 77 games with the San Francisco Giants in 2012. David J. Phillip/Pool/Getty Images

2013 Red Sox

Acquired Jake Peavy from White Sox

The Red Sox had a 3.77 ERA through July 31. Peavy threw 64 2/3 innings for Boston, lasting at least six innings in all but two of his 10 starts. Peavy made six August starts for the Red Sox, giving up two earned runs or fewer in all but one of those in helping Boston stretch their division lead from 0.5 to 4.5 games in that month alone. In his postseason opener, Peavy went 5 2/3 innings and allowed just one earned run.

2014 Giants

Acquired Peavy from Red Sox

The Giants had just placed Matt Cain on the disabled list after elbow surgery, ending his season. They acquired Peavy on July 26 and from that date on, Peavy led all Giants’ starters in ERA with 2.17, ahead of even Madison Bumgarner’s 2.59 mark. In his first two postseason starts, Peavy allowed two runs combined.

2015 Kansas City Royals

Acquired Johnny Cueto from Reds, Ben Zobrist from Athletics

Cueto had a 2.62 ERA with the Reds but posted a 4.76 mark during his time with the Royals in the regular season. In the postseason, however, Cueto stepped up his game big time. He went six innings in the Royals’ ALDS Game 2 win against the Astros. In the decisive Game 5, Cueto went eight innings, giving up two earned runs and striking out eight as the Royals took the series. In Game 2 of the World Series, he went the distance, allowing just one run on two hits.

Zobrist batted .284 during his time with the Royals. He hit .303 during the playoffs with two home runs, six runs batted in and five multi-hit games. Zobrist hit first-inning home runs off R.A. Dickey and David Price in the ALCS.