Ice Cube clearly thinks Caitlin Clark can succeed in the Big3 ... but one man who's convinced she can't is ex-NBA star Kenyon Martin, who said Wednesday she wouldn't be able to score a single point in the 3-on-3 league. The Iowa Hawkeyes star received a $5 million offer to join Cube's hoops org. on Wednesday ... but when Martin was asked how he thinks she'd fare if she accepted the deal -- he made it clear, he thinks it'd be a mess. "It's a step under prison ball," the former NBA player said of the Big3's action on Gilbert Arenas' "Gil's Arena Show." "Could you imagine her getting stuck down on Reggie Evans?" Arenas himself wasn't convinced she'd find success either ... saying she's just too small at 6 feet, 155 pounds to compete in a league with a bunch of former ex-NBA giants. "She gon' take the ball out?" he asked. "As soon as she tries to cross that line -- boom! Yo' little ass." WNBA star Lexie Brown -- who was also a guest on the show -- disagreed with both guys ... but the former NBA stars were adamant she'd struggle. Nonetheless, Cube obviously thinks it'd be a great experience ... agreeing to send her huge checks in exchange for playing in as few as eight games. "This is a special situation," he said Wednesday afternoon, "a special player that's moving the needle in a lot of different areas, you know, ratings, attendance, ticket sales." As for whether or not Clark will take the contract ... that's all unclear -- Cube added on Wednesday he's yet to hear a definitive "yes" or "no" from the talented hooper.