There are five reasons the Dodgers face a bigger challenge in overcoming early season struggles -- similar to the ones they had a year ago -- as they look to defend their National League West crown:

1. Madison Bumgarner
2. Tim Lincecum
3. Ryan Vogelsong
4. Tim Hudson
5. Matt Cain

Otherwise known as the San Francisco Giants' starting rotation.

A season ago, the Dodgers stumbled into June with a 23-30 record, in last place in the NL West, but only 6 1/2 games behind Arizona. This year, the Dodgers entered the final day of May with a 29-27 record -- tied for second place in the division with the Rockies, 7 1/2 games back of the Giants.

In winning two of the last four World Series, San Francisco has relied on a dominant rotation for its success. In the two other campaigns, the Giants' starters have struggled.

Well, the Giants rotation is back in charge in 2014. Yes, Cain was retroactively placed on the disabled list on Friday, but the club isn't concerned about a long-term problem with his strained right hamstring. In fact, it has plans for Cain to be activated in time to start against the Mets next weekend in the opener of a 10-game homestand.

In falling below .500 a year ago (76-86), the Giants' pitching rotation was 49-56 with a 4.37 ERA, the rotation's highest ERA and only losing record in seven years. With the addition of Hudson -- signed as a free agent to replace Barry Zito -- and a resurgence by Vogelsong, San Francisco has seized control of the NL West.

The Giants allowed two or fewer runs in 26 of their first 55 games, which helps offset an inconsistent offense. But even the offense has gotten a lift with the May revival of Pablo Sandoval, who in the 10 days prior to Saturday was 15-for-36 (.417) with five home runs and 14 RBIs.

The Dodgers, meanwhile, have been unable to put together a solid stretch -- despite an impact year from Yasiel Puig, who entered Saturday hitting .346 with 11 home runs and 40 RBIs, and the emergence of Dee Gordon as a godsend at second base and at the top of the lineup. Gordon has hit leadoff in 43 of his 49 starts, and has a .344 on-base percentage and is 34-for-37 stealing bases in those games.

The aging roster has been hit with injuries, and the concerns continue to grow about Matt Kemp. He now finds himself moved from center field to left field, a position he hadn't played since he was a 21-year-old rookie in 2006. Kemp was given an eight-year, $160 million deal after hitting .324 with 39 home runs, 126 RBIs and 40 stolen bases in 2011. Since then, however, he has made six trips to the disabled list, and went into Saturday with a composite .281 average, 34 home runs, 115 RBIs and 23 stolen bases in 225 games since Opening Day 2012.

The rotation
• The Nationals were a trendy pick to win the NL East, but they have struggled to stay above .500. Then again, five members of their Opening Day lineup -- Bryce Harper, Denard Span, Ryan Zimmerman, Adam LaRoche and Wilson Ramos -- have been in the lineup together for only seven innings this season. Each has spent time on the disabled list.

• Oakland third baseman Josh Donaldson went into Saturday with 47 runs scored and 45 RBIs, the only player in the big leagues who has at least 40 in both categories.

• With two out in the bottom of the 10th inning at Milwaukee on Tuesday, and the scored tied at 6, Baltimore manager Buck Showalter opted to intentionally walk Mark Reynolds with nobody on base and the pitcher's spot due up. Brewers manager Ron Roenicke countered by sending Yovani Gallardo up to pinch-hit, and he delivered a game-ending double. The last pitcher with a walk-off pinch-hit? Glendon Rusch, also with the Brewers on April 19, 2003.

• Gallardo started and won Wednesday's game. Bud Norris, who had a sacrifice bunt for the Orioles the night before, started for Baltimore. It was the first time two pitchers started against each other the game after they both were used as pinch-hitters since Tom Browning of Cincinnati faced Atlanta's John Smoltz on July 29, 1989, according to the Elias Sports Bureau.

Numbers game
.571: The batting average for Rockies shortstop Troy Tulowitzki at Coors Field. Rogers Hornsby set the record for home average (.478) with the Cardinals in 1925. Former Rockies outfielder Larry Walker is fifth on the all-time list with a .461 home average in 1999.

16: Home runs for Edwin Encarnacion in May, entering Saturday's final game of the month. That matches Mickey Mantle's AL record for the month, set with the Yankees in 1956. Encarnacion is one shy of the Major League record Barry Bonds set with the Giants in 2001, the year he had a record 73 homers. Sammy Sosa set the single month record, with 20 in June 1998.

6: Different hitting coaches for Kansas City since the first week of 2012. This week, the Royals moved third-base coach Dale Sveum into the hitting-coach position, reassigning Pedro Girfol to be the catching coach. In addition to Sveum and Girfol, Kevin Seitzer, Jack Maloof, Andre David and George Brett have worked with Royals hitters since the start of 2012.

TMI
The Washington Senators/Minnesota Twins have not been no-hit at home since the advent of the American League in 1901, according to notes guru Bill Arnold. The franchise has played 8,877 home games as a member of the AL. The Senators/Twins have been no-hit nine times, all on the road. Then, there are the San Diego Padres, who went into Saturday having never had a pitcher throw a no-hitter in the 7,219 games in franchise history. The Padres are the only team to not have a pitcher throw a no-hitter. They have, however, been no-hit eight times since their creation as an expansion team in 1969.