Right-hander Josh Johnson was originally scheduled to pitch on Monday, but he has now been pushed back until Wednesday. Blue Jays manager John Gibbons said Johnson could use some additional rest after he experienced right forearm tightness during his last start against Seattle.
"No, he's good. We don't think it's a big deal," Gibbons said when asked if Johnson could be in danger of missing additional time.
Happ will be making his start against Oakland on normal rest because of Toronto's off-day on Thursday. He is a candidate to be placed on the three-day bereavement list after Monday's game, which would create an open spot on the 25-man roster.
That spot would then likely be filled by right-hander Todd Redmond, who is scheduled to be recalled from Triple-A Buffalo for Tuesday's start against Boston. Esmil Rogers was expected to make that start, but instead has been moved back to the bullpen following his prolonged struggles on the mound.
Rogers was 0-4 with an 8.50 ERA over his past seven starts and hadn't won since June 18 against Colorado. He performed admirably when he first entered the rotation in late May, but appeared to be hitting a wall of late. He already thrown more innings this season than he did all of last year.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.