Bello will start in Sunday's series finale against Atlanta, Tim Healey of The Boston Globe reports.
The right-hander has worked behind opener Jovani Moran in each of his last two outings, but Bello will be the starter for Sunday's contest, rather than operate in a bulk-relief role. The 27-year-old pitched well in those last two appearances, allowing two runs and eight hits and two walks while striking out 12 across 13.1 innings.