In a casting straight out of fan central, Katee Sackhoff, best known for her role as Kara “Starbuck” Thrace on “Battlestar Galactica,” has been tapped to co-star on another series with a big fan following, Fox’s “24.” Sackhoff will play Dana Walsh, a smart, competent, expert data analyst at CTU with a secret past who is involved with CTU agent Davis Cole (Freddie Prinze Jr.). Sackhoff was close to committing to “24” a week ago, but with another lucrative offer from a cable network on the table, she took herself out of contention to mull her options.