The left-hander is headed for surgery to repair a fracture in his right foot, the origin of which isn't entirely clear. Happ, who was scheduled to start the middle game of three against the Red Sox at Fenway Park this weekend, is being replaced in the rotation by another southpaw, Aaron Laffey.
Happ irritated his right ankle covering first base at Yankee Stadium on Aug. 29, but the problem at the time didn't appear to be with his foot. Tests were performed in New York, and Happ made another start, on Monday in Baltimore.
"We're not quite exactly sure," manager John Farrell said when asked when the fracture occurred. "The play at first base irritated his ankle, where he was feeling the discomfort at the time, and when that discomfort lingered, we had an MRI done. In New York, when he was examined, the X-rays were negative, yet the discomfort wasn't thoroughly going away."
Happ went for followup exams, including a CAT scan and another MRI, that revealed the fracture.
"At this point the recommendation is to have surgery, and his season is over," Farrell said.
The 29-year-old Happ made six starts and 10 appearances for Toronto after arriving from Houston as part of the 10-player deal in July. He went 3-2 with a 4.46 ERA in 40 1/3 innings following the trade, with a strong strikeout rate: He fanned 46 to go along with 17 walks and two home runs allowed.
Happ is the fourth Toronto starter this season to sustain a major injury: Drew Hutchison and Kyle Drabek are both out for the year after undergoing Tommy John surgery, and Brandon Morrow returned on Aug. 25 after recovering from an oblique injury that kept him out more than two months. Ricky Romero and Henderson Alvarez are the only two starters who have remained healthy all season.
"We come in here today with a rotation that's mapped out, and yet you come into the ballpark, you're waiting for the next phone call, and in this case, J.A. Happ is out for the year," Farrell said. "[We're] not ... on Plan A or B; [we're] on Plan T or U. That's where we're at."
Farrell was pleased to get the time from Happ that he did.
"Yes, without a doubt," he said. "You got a guy coming over from the National League, you want to see how they play through the lengthened-out lineups with the DH. ... He's thrown the ball very well."
With Laffey back in a starting role, the Blue Jays called up right-handers David Carpenter and Joel Carreno on Friday to pick up the workload in the bullpen. Carpenter, another piece of the Houston trade, has one appearance (in relief) for Toronto this season, whereas Carreno has made seven, two of them starts. Carpenter, 27, has a 7.12 ERA in 31 Major League outings this season; Carreno, 25, has a 6.35 ERA with a big league club.
"When we got the first initial results on [Happ's] MRI and the CAT scan, we knew we were going to need additional arms," Farrell said. "The potential for less innings out of the rotation might exist, particularly if we're going to a six-man rotation."
Farrell said that the team may want to get Chad Jenkins a start at some point. Romero's turn in the rotation is being skipped this time around as he continues to struggle.