The Rays selected Guerra from Triple-A Durham on Monday, Tricia Whitaker of Bally Sports Sun reports.
Guerra will provide depth in the bullpen during this week's four-game series in Toronto-and possibly beyond-in his first big-league stint since early July. The righty has a 10.80 ERA in 8.1 MLB innings this season and has yielded four earned runs in his last three minor-league innings, suggesting he won't see any high-leverage work while with the Rays.