Reliever Justin De Fratus began his rehab assignment Sunday with Class A Clearwater, pitching a scoreless inning in his season debut.

DeFratus, rehabbing from a sprained right elbow, faced four batters and allowed a double to rightfield. He recorded two flyouts and a groundout in the Threshers' 4-2 win over Brevard County as the starting pitcher.

"Another symptom free outing! I can see the light at the end of the tunnel. #superstoked," De Fratus tweeted.

De Fratus was ranked as the seventh-best prospect in the Phillies organization by Baseball America last fall.

Scheduled starter Austin Wright pitched five innings in relief of DeFratus and struck out 10. He improvoed to 3-0 on the season and has struck out 23 in 16 innings.