"They're just coming into their own," Jackson said of the two 24-year-old Cubs. "The more they get the chance to play, the more they get a chance to discover themselves and realize what they're able to do.
"They're All-Star-caliber players and the quicker they realize it and take the field with that type of attitude, it shows in their play."
Rizzo has 14 home runs since April 30, the most in the National League, and he is tied for sixth-most in the Majors. He has 35 walks, a .395 on-base percentage and a .937 OPS in his last 56 games dating to April 30. The Cubs first baseman also has 11 doubles, 14 homers and 34 RBIs during this stretch.
Of his 11 homers since May 8, nine have given the Cubs the lead and one has tied the game.
"I know there's a lot of competition at first base," Rizzo said. "But National League, they can use extra players. ... It would be really cool [to be selected]. It would be awesome."
Castro's 11 home runs and 47 RBIs this season top the 10 homers and 44 RBIs he totaled in 161 games last year. He is batting .286 and has 93 hits, second among all NL shortstops, trailing only the Rockies' Troy Tulowitzki. Castro's 37 extra-base hits are the most among Major League shortstops.
"I'm excited that day is coming," Castro said of Sunday, when the All-Star teams are announced. "If it happens, I'll be really happy, me and my family. After last year, a lot of bad things happened, and it would be cool for me to be back in the All-Star Game."
The goal now is to keep it going for the entire season.
"I feel good now physically, everything, my mind is strong. Hopefully, I'll make the All-Star Game," Castro said.
"They've made some vast improvements in their game, and they continue to learn and continue to adjust," Cubs manager Rick Renteria said of Castro and Rizzo. "They do impact us in a big way, and in many different facets. They deserve a nod, as, quite frankly, Jeff [Samardzija] and [Jason Hammel]. I know I say I'd throw everybody in there, but those four have gone out and done a nice job."
Fans can cast their votes for starters at MLB.com and all 30 club sites -- online or on a mobile device -- using the 2014 All-Star Game MLB.com Ballot Sponsored by Experian until Thursday at 10:59 p.m. CT. The 2014 All-Star Game will be played at Target Field on Tuesday, July 15.
Fans may submit up to 25 online ballots, but they can also earn a one-time bonus of 10 additional online ballots. To access these additional online ballots, you must be logged into your MLB.com account when you submit any online ballot. If you do not have an MLB.com account, register on the site in accordance with the enrollment instructions for a free MLB.com account.
Fans this year once again can participate in the Home Run Derby Fan Poll. Fans will have the opportunity to select three players in each league who they would most like to see participate in the Gillette Home Run Derby. The 2014 Home Run Derby will be broadcast live on ESPN, ESPN HD, ESPN Deportes and ESPN Radio in the United States beginning at 7 p.m. on Monday, July 14.
The 2014 American League and NL All-Star teams will be unveiled on the Taco Bell All-Star Selection Show on Sunday, beginning at 6 p.m. on ESPN, with further details to follow on MLB.com. Immediately following the announcement of the AL and NL All-Star rosters, fans can begin voting to select the final player for each league's 34-man roster via the 2014 All-Star Game MLB.com Final Vote Sponsored by Experian. Fans will cast their votes from a list of five players from each league over the balloting period.
And the voting doesn't end there. The final phase of All-Star Game voting will again have fans participating in the voting for the Ted Williams All-Star Game Most Valuable Player Award presented by Chevrolet. During the Midsummer Classic, fans will vote exclusively online at MLB.com via the 2014 All-Star Game MLB.com MVP Vote Sponsored by Pepsi, and their voice will represent 20 percent of the overall vote that determines the recipient of the Arch Ward Trophy.
MLB.com will provide extensive online coverage of the All-Star Week festivities.
The 85th All-Star Game will be televised nationally by FOX, in Canada by Rogers Sportsnet and RDS, and worldwide by partners in more than 200 countries via MLB International's independent feed. ESPN Radio and ESPN Radio Deportes will provide national radio coverage of the All-Star Game. MLB Network and SiriusXM will also provide comprehensive All-Star Week coverage. For more information, please visit allstargame.com.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.