A 32-year-old man is brought to the emergency department following a high-speed motor vehicle collision. On primary survey, he is haemodynamically stable (BP 118/76 mmHg, HR 92/min). Physical examination reveals tenderness in the left upper quadrant with mild guarding. FAST (Focused Assessment with Sonography for Trauma) shows free fluid in the splenic fossa. CT abdomen with IV contrast demonstrates a Grade III splenic laceration with active contrast extravasation. What is the most appropriate immediate management?