Also missing is Kevin O'Brien due to family commitments - his wife Ruth-Anne is due to give birth to their first child this week.
Merrion all-rounder Tyrone Kane is also absent for the three-day clash at Clontarf against the Knights - he has university exams.
Leinster's Irish passport holding Australian Joe Carroll is drafted in, while Malahide and Ireland speedster Peter Chase also makes a welcome return.
Lightning have also named their squad for the T20 clash with the Warriors at Merrion next Friday.
Ireland U19 star Lorcan Tucker returns following exams replacing Grassi, while Lightning will be boosted by the availability of both O'Brien and Kane.
LIGHTNING SQUAD FOR 3 DAY GAME V KNIGHTS (Clontarf , May 10-12, 11am)
John Anderson (Capt-Merrion); Yaqoob Ali (YMCA); Joe Carroll (Leinster); Peter Chase (Malahide); George Dockrell (Trinity/Leinster); Jamie Grassi (North County); Dom Joyce (Merrion); Andrew Poynter (Clontarf); Eddie Richardson (North County); Simi Singh (YMCA); Max Sorensen (The Hills); Jack Tector (YMCA).
LIGHTNING SQUAD FOR T20 V WARRIORS (Merrion, May 13, 5pm)
John Anderson (Capt-Merrion); Yaqoob Ali (YMCA); Joe Carroll (Leinster); George Dockrell (Trinity/Leinster); Dom Joyce (Merrion); Tyrone Kane (Merrion); Kevin O'Brien (Railway Union); Andrew Poynter (Clontarf); Eddie Richardson (North County); Simi Singh (YMCA); Max Sorensen (The Hills); Lorcan Tucker (Trinity).