The Red Sox optioned Bello to Triple-A Worcester on Friday.
The move opens up a spot on the 26-man roster for trade pickup Joe La Sorsa, who was acquired from the Pirates earlier in the week. Bello has been hammered for a 6.34 ERA, 1.67 WHIP and an American League-high 43 earned runs across 61 innings this season. He'll try to figure things out in the minors.