Hernandez's bobblehead will feature "King Felix" in a crown and royal robe, while Rodney's will show the closer launching his patented imaginary arrow following a save.
Postgame fireworks have been expanded to four games and will be themed. They are scheduled for May 29 (I Love the 90s), June 19 (Star Wars), July 24 (Sing Along) and Aug. 21 (Songs of the Summer).
There also will be five hat giveaways this season: the third annual Beard Hat Night (April 17), Hisashi Iwakuma "Bear" Hat (April 25), Mother's Day sunhat (May 10), Mariners fedora (May 15) and the Negro League Seattle Steelheads (May 16). The first 20,000 fans at each game will receive the corresponding hat, excluding the Mother's Day sunhat, which will go to the first 10,000 moms.
The club will give away another Mariners Express train car, with the Dustin Ackley "Ack Attack" car going to the first 20,000 fans on June 6, while Bark at the Park returns July 9.
For younger fans, there are two Salute to Kids Days on April 26 and Aug. 23, and four Little League Days (May 10, 17 and 31, as well as June 7). Youth Baseball Day is June 21.
Nelson Cruz Bat Night is May 30, while the season concludes with Kids Appreciation Day on Oct. 4.
There will be two Guys Nights (April 24, July 10) and two Girls Nights (May 8, Aug. 7), as well as four College Nights (April 17, May 15, June 5 and Sept. 12).
For the complete promotional schedule, as well as other family, senior and military specials, visit mariners.com/tickets.
Cash Kruth is a reporter for MLB.com. Follow him on Twitter at @cashkruth. This story was not subject to the approval of Major League Baseball or its clubs.