When Zoro decided to stay behind, the main focus Oda pointed out, resolved around the fact it was a government island, suggesting that you'd never know who'd be coming, so with Kizaru coming to Egghead, guess he'd end up intercepted by Zoro, who he almost killed preskip, so most likely with Zoro wanting a pay back
With that said, Kizaru was also the only admiral we know of, who Vegapunk had a connection with(we know that Vegapunk replicated his lasers on Pacifistas), and Sentoumaru was also his subordinate in Sabaody, and thus tying him nicely into the arc i guess