Because of the heat and the overall grind of a long season, August is commonly referred to as the "dog days" in Major League Baseball. But for a flock of rookies across both leagues, it seemed that nothing could get them down last month.

Now, it's time for fans to reflect on the performances and help decide which of those rookies deserve special recognition as balloting is under way for the American League and National League August Rookie of the Month awards presented by Gillette.

The AL nominees are Minnesota starter Glen Perkins, White Sox second baseman Alexei Ramirez and Minnesota outfielder Denard Span The NL nominees are St. Louis reliever Chris Perez, Cubs' reliever Jeff Samardzija, Cubs catcher Geovany Soto and Colorado third baseman Ian Stewart.

Fans can cast their Rookie of the Month votes through Monday at mlb.com/gillette.

Stewart has the opportunity to go back-to-back in the Rookie of the Month balloting. He was selected as the July winner from the NL and didn't rest on that accomplishment. Stewart helped keep the Rockies within striking distance in the NL West by hitting .295 in August with five homers, 20 runs batted in, 28 hits, 18 runs scored and 17 walks.

Perez helped stabilize the back end of the Cardinals bullpen while recording six August saves in eight appearances. The hard-throwing right-hander did not allow a run in 9 1/3 innings and surrendered just three hits. Perez had 12 strikeouts over that span.

Samardzija provided a bullpen boost for the first-place Cubs. In 14 1/3 innings, he was 1-0 and didn't allow a run. Samardzija had 13 strikeouts during the month. Soto won rookie honors in April and has continued to be a firm offensive and defensive presence for a Chicago team that has taken charge of the NL Central. Soto hit .355 in August with five doubles, three homers and 21 RBIs. Soto drew 13 walks and scored 17 runs while handling himself well behind the plate and providing a level of comfort for the Chicago pitching staff.

There were equally notable rookie performances in the AL.

Perkins bolstered the Minnesota starting rotation by going 4-0 in August with a 3.31 earned-run average. Perkins made five starts and had two signature outings. The left-hander threw eight shutout innings against the Yankees on Aug. 11 and eight shutout innings against the Angels on Aug. 22.

Ramirez continues to be a big reason why the White Sox are in a neck-and-neck battle with Minnesota for the AL Central title. The second baseman hit .308 in August with six homers and 22 RBIs. Ramirez had a four-hit game against Baltimore on Aug. 25.

Span has been a catalyst for the surprising Twins, who are contending once again despite losing star center fielder Torii Hunter via free agency last winter. Span hit .292 in August with three homers, 23 RBIs, 35 hits and 20 runs scored.

Gillette will present the award winners with a Rookie of the Month trophy following the announcement and make a donation to a charitable organization in the award recipient's name. The online fan vote represents 20 percent of the overall vote, with the remaining votes coming from team baseball writers and club broadcasters. Voters for the monthly rookie awards will be automatically registered for a chance to attend one game during the World Series this October.

Gillette continues to make significant media commitments to national Major League Baseball rights holders, This Week in Baseball presented by Aquafina, produced by Emmy-Award winning Major League Baseball Productions, and to MLB Jewel Event publications created by MLB Properties.