Lester had cruised through the first seven innings, allowing just two runs and three hits before allowing back-to-back singles to begin the eighth. After running the count to 3-0 on Emilio Bonifacio, Red Sox manager John Farrell came running to the mound as the infield crowded around Lester.
Lester then walked off the field as reliever Junichi Tazawa came on in relief.
Lester retired 10 straight to begin the game and didn't allow a hit until the fifth inning, seemingly on pace for his second complete game this season - the other also coming against Toronto on May 10.
Lester had thrown just 94 pitches when he left. He was charged with four runs and five hits over seven-plus innings, striking out five and walking three.
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