Bello (forearm) threw 72 pitches over five innings in an extended spring training start Wednesday, Jen McCaffrey of The Athletic reports.
Bello had been in line to begin his rehab assignment at Triple-A Worcester on Wednesday, but due to inclement weather in the Northeast, he threw at Red Sox camp in Florida instead. Assuming Bello feels fine physically coming out of Wednesday's outing, he'll likely need just one more rehab start before coming off the 15-day injured list. Garrett Whitlock (hip) appears on track to beat Bello back from the IL, so the Red Sox may not have a spot in the rotation immediately available for Bello once he's activated.