Miller was a pitcher at Kettering High in Waterford, Mich., where he was named all-state, all-league and all-district. He was twice selected in Major League Baseball's amateur draft, but opted to focus solely on football after playing baseball as a freshman at Michigan State.
Mannelly is in the process of trying to land two more Bears teammates for the Celebrity Home Run Challenge, which is slated to begin at 6 p.m. Kittle's team will also feature former Bulls player Dave Corzine.
The celebrities will take aim at a series of "money zones" designed to raise funds for charitable causes, with Miller and Mannelly stepping to the plate for Bears Care.
The money zones will be marked off in the stadium's outfield and charity funds will also be credited for any ball hit out of Alexian Field. The top distance hitters from each team will advance through the first two rounds and a tournament winner will be crowned in the third round.
Miller, 31, emerged as one of Chicago's marquee athletes last year, compiling an 11-2 record as a starter in leading the Bears to their first NFC Central championship since 1990. This spring he signed a five-year contract to remain the club's starting quarterback.
Mannelly, 27, is considered one of the NFL's top long-snappers. His wife, Tamara, is the daughter of baseball great Tommy John.
Kittle, 44, was the 1983 American League Rookie of the Year as a member of the AL West Champion White Sox. He managed the Flyers from 1999-2001.
Corzine, 46, played for the Bulls from 1982-89 during a 13-year NBA career.