The official episode description for 9.17 “Checkmate”, airing on Friday April 9th:

“SMALLVILLE” — (8:00-9:00 p.m. ET)
“Checkmate” (TV-PG) (HDTV)

PAM GRIER (“JACKIE BROWN,” “THE L WORD”) GUEST STARS AND PHIL MORRIS RETURNS AS MARTIAN MANHUNTER — Tess (Cassidy Freeman) creates an elaborate hoax in order to kidnap Green Arrow (Justin Hartley) and delivers him to Amanda Waller (guest star Pam Grier), who tells him that that the government is recruiting him to serve his country. However, Green Arrow escapes before they can reveal his identity. After Oliver brings Clark (Tom Welling) and Chloe (Allison Mack) up to speed, the three investigate and Clark is surprised to find John Jones (guest star Phil Morris.) investigating Oliver’s kidnapping too. Clark senses that John is keeping information from him. Oliver and Clark are shocked when Tess reveals that Amanda is after something called “Watchtower.” Waller threatens to kill Chloe unless Clark gives her the names and locations of the rest of the Justice League. Tim Scanlan directed the episode written by John Chisholm (#X3X5267)

SOURCE: SpoilerTV