Snell was optioned to Triple-A Durham on Friday, Marc Topkin of the Tampa Bay Times reports.
The southpaw has followed a dynamic rookie season with a disappointing 2017 campaign, in which he's racked up a 4.98 ERA over 14 starts and lasted just four innings in his last outing. Although Snell exhibited some improvement by posting a 3.80 ERA in four starts last month, the Rays appear to have lost patience and will search for alternative starters while he works things out in the minors. It's unknown as to who will take the vacant rotation spot, though Jake Odorizzi -- currently sidelined with a back injury -- may be an option.