The Toronto Blue Jays made the announcement on Friday, less than 24 hours after Norris needed 78 pitches to get through three scoreless innings in the team's 5-1 win at Cleveland.
Norris, 22, went to a full count on seven of 15 hitters he faced, pitched his way through a 38-pitch second inning without being scored upon and lowered his season earned-run average to 3.86.
But opponents have hit .267 against the left-hander, so he'll work on his game with the Bisons until further notice.
"It just shows the type of competitor he is," said Blue Jays catcher Russell Martin of Norris' ability to pitch out of trouble. "I'd like to see him breathe a little bit and relax and not put so much pressure on himself."
Norris won a starting job out of spring training after posting a 2.93 ERA in seven pre-season starts and striking out 30 over 27 2/3 innings while walking only eight.
But after beating New York at Yankee Stadium on April 9, Norris struggled in three of his next four outings. He entered Thursday's contest fresh off a seven-inning gem at Tampa Bay on April 25 in which he fanned seven and limited the Rays to five hits and one earned run.
The Blue Jays' top pitching prospect, Norris entered this season with 6 2/3 innings on his major league resume.
He started one game for Toronto in September after compiling a 2.53 ERA across three minor-league levels
In October, Norris had arthroscopic surgery to remove bone spurs and loose bodies in his left (throwing) elbow.
Also Friday, the Blue Jays recalled Canadian lefty Andrew Albers from Buffalo. He'll join the bullpen in Cleveland this weekend.
To make room for Albers on the 40-man roster, Toronto moved injured infielder Maicer Izturis to the 60-day disabled list.Suggest a correction