According to TVInsider, Shipp has a role to play in this year's five-show Arrowverse crossover. However, there's no word yet on which role he will reprise for the event.
Throughout his Arrowverse tenure, Shipp has played three separate characters: Henry Allen, Jay Garrick and the Barry Allen of Earth-90. Henry died in Season 2, so it likely won't be this character. In Season 4, Jay announced his plan to train a new Flash for Earth-3, after which he would retire from the superhero life. As such, it's possible for Jay to return with his new trainee in tow.
Most likely, Shipp will play Earth-90's Barry Allen in "Crisis on Infinite Earths." This character managed to impress the Monitor during "Elseworlds," last year's crossover; Shipp's Barry managed to survive his own Earth's destruction when no one else did. When the Monitor realized this, he zapped the character away, never to be seen or heard from again. It seems, then, that the Monitor had other plans for Barry -- although we don't know what those are just yet.
"Crisis on Infinite Earths" already has a star-studded list of guest stars. Batman: The Animated Series star Kevin Conroy, Black Lightning's Cress Williams, Batman 1966 star Burt Ward, Legends of Tomorrow's Jonah Hex and "Elseworlds" alums Tyler Hoechlin and Elizabeth Tulloch are among those appearing the crossover. DC's Legends of Tomorrow star Brandon Routh will also suit up as Kingdom Come Superman.
"Crisis on Infinite Earths" begins Sunday, December 8 at 8 pm ET/PT on Supergirl, then continues in Batwoman on Monday, December 8 at 8 pm ET/PT and in The Flash on Tuesday, December 10 at 8 pm ET/PT. After the winter hiatus, the crossover will conclude on Tuesday, January 14 in Arrow at 8 pm ET/PT and in DC's Legends of Tomorrow at 9 pm ET/PT.