Overton, 31, suffered the injury while attempting to take a return catch off Keacy Carty just two deliveries into his opening spell. He left the field immediately for treatment and, though he later returned with his finger heavily strapped, subsequent scans confirmed a fracture rather than a dislocation.
Despite the setback, Overton made a strong impact in England's 238-run victory, finishing with figures of 3 for 22 in 5.2 overs. His dismissals included Roston Chase and Matthew Forde with short-pitched deliveries, as well as Gudakesh Motie, who fell to a well-disguised slower ball.
He will now begin a period of rehabilitation under the supervision of the ECB medical staff. England have opted not to name a replacement, with Matthew Potts and left-armer Luke Wood already in the squad as reserve seam options. Left-arm spinner Tom Hartley may also come into contention for selection.
The second ODI will be played in Cardiff on Sunday, with the final match of the series scheduled for Tuesday at The Kia Oval. The T20I leg of the tour begins on Friday at Chester-le-Street.
Ryan Rickelton has shed light on the evolution of his relationship with Proteas head coach Shukri Conrad, revealing how a once-turbulent dynamic has matured into mutual respect ahead of South Africa's World Test Championship final against Australia.
England launched the Harry Brook's tenure as captain in emphatic style after crushing West Indies by 238 runs in the first One-Day International at Edgbaston on Thursday - their second-largest winning margin by runs in ODI history.
South African cricket fans can look forward to a packed home Test calendar in 2026-27, with the Proteas scheduled to host eight matches - but not before sitting out a full season of red-ball cricket on home soil.
Brian Bennett scored Zimbabwe's fastest ever Test century but England were still well on top after two days of the historic one-off fixture at Trent Bridge in Nottingham.
