Bryce Harper had a chance to shine in front of his home fans during the All-Star break, and he took advantage by winning the Home Run Derby .

Then it was back to reality for Harper and the Washington Nationals, who will need to turn things around soon if they want to avoid a disappointing season.

After hosting the All-Star festivities, Washington split two home games against NL East rival Atlanta, with a postponement in between. In a loss Friday night, the Nationals' frustration seemed evident when star pitchers Max Scherzer and Stephen Strasburg had a heated exchange in the dugout. Even after a win Sunday, Washington is six games behind first-place Philadelphia and five behind the Braves, who are in position for the second wild card.

Harper has taken a lot of the heat for Washington's underachieving, and his .218 batting average certainly sticks out. But he does have 24 homers and a .366 on-base percentage, so it's not as though his offensive approach has completely fallen apart.

Harper is one of a handful of players on contending teams who may be primed for big improvements in the second half this year — and who could still have a big impact on the postseason races. Here are a few others:

— Jon Gray, Rockies. Gray may be baseball's biggest enigma at the moment. He's averaging 11.33 strikeouts per nine innings, the second-best mark in the National League, but he's just 8-7 with a 5.44 ERA. A .381 batting average on balls in play is a major culprit in his struggles, so he could be a good bet to turn things around, but the Rockies were sufficiently concerned that they sent him down to the minors briefly before the break. After returning, he pitched impressively into the eighth inning against Seattle on July 14.

Colorado made the postseason last year and is currently just two games behind the NL West-leading Dodgers, so if Gray pitches well down the stretch, the Rockies could remain in the mix again.

— Nick Pivetta and Vince Velasquez, Phillies. The rest of the NL East better hope these two don't hit their stride any time soon. They've both struck out nearly as many hitters as staff ace Aaron Nola, despite significantly fewer innings. But consistency has been elusive. Pivetta has been strong with the exception of two awful starts against the Nationals in which he allowed a total of 13 runs in 2 2/3 innings. Velasquez gave up 10 runs against Milwaukee on June 8 but has held opponents to two or fewer in five of his six starts since then.

— Kyle Seager, Mariners. Seattle has a solid shot to make the postseason, but its steady third baseman may be having the worst offensive year of his career. He's hitting just .233 with an unsightly .284 on-base percentage. If the season ended now, the Mariners would be a wild card, but they're in this position largely because of a 26-12 record in one-run games. Their margin for error appears thin.

Other developments from around the majors:

BUY OR SELL?

The trade market is active with the deadline looming. Manny Machado went from Baltimore to the Dodgers , while the Athletics and Indians acquired relievers Jeurys Familia and Brad Hand , respectively. The teams giving up those three players — the Orioles, Mets and Padres — are all in last place, but it will be interesting to see how some of the borderline contenders approach the deadline.

That's especially true in the NL, where 11 of the 15 teams are at .500 or better — but nobody has a winning percentage higher than .592. A lot of teams could theoretically make a push for the postseason, but only five can get in.

HIGHLIGHT

Sunday's game was already going badly for Milwaukee when infielder Hernan Perez came on to pitch in the seventh inning against the Dodgers. Perez actually made it through two scoreless innings, but his attempt to change speeds against Austin Barnes was laughable. Perez threw a pitch clocked at 48 miles per hour that hit Barnes in the back.

Perez retired six of the next seven hitters after that.

LINE OF THE WEEK

Matt Carpenter of St. Louis hit three home runs and two doubles Friday, tying the major league record for extra-base hits in a game and driving in seven runs in an 18-5 victory over the Chicago Cubs. That was part of a six-game homer streak for Carpenter that ended Sunday.