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05/08/2013 8:22 PM ET

Blue Jays yet to decide on Happ's replacement

ST. PETERSBURG -- The Blue Jays have yet to make a decision on who will replace left-hander J.A. Happ in the rotation following Tuesday night's scary scene at Tropicana Field.

Happ was struck in the head by a line drive off the bat of Tampa Bay's Desmond Jennings. The Toronto left-hander was diagnosed with a minor skull fracture and has since been placed on the 15-day disabled list. He was released from Bayfront Medical Center Wednesday afternoon after undergoing a series of tests and a CT scan.

The Blue Jays selected the contract of right-hander Edgar Gonzalez to replace Happ on the 25-man roster, but the club likely will make another roster move this weekend.

"We're worrying about tonight's game," Toronto manager John Gibbons said when asked who would make Happ's scheduled start on Sunday. "When it gets a little closer to that day, we'll let you know."

Veteran right-hander Claudio Vargas could be one candidate to make a spot start as the club waits to see how long No. 4 starter Josh Johnson will be on the disabled list with soreness in his right triceps muscle.

Vargas was scheduled to pitch for Triple-A Buffalo on Wednesday night, but if his outing is relatively short, he could come back on three days' rest to face Boston on Sunday afternoon.

Double-A New Hampshire right-hander Chad Jenkins would be a stronger candidate to make the outing, but he just recently returned from a right shoulder injury. Jenkins made his first start of the season on Monday and allowed three hits and two runs in five innings as he continues to build up endurance.

Jenkins appeared in 13 games -- including one start -- for the Blue Jays last season and posted a 4.50 ERA in 32 innings. The 25-year-old was a first-round pick in the 2009 First-Year Player Draft.

The Blue Jays have off-days next Monday and Thursday, so it's possible the club won't need a fifth starter after Sunday until May 21.

DeRosa makes rare start at second base

ST. PETERSBURG -- Blue Jays veteran infielder Mark DeRosa made a rare start at second base for Wednesday night's game against Tampa Bay.

DeRosa previously made four appearances at second base this season, but had yet to receive a start. Before Wednesday, he played a few innings at the position after coming into games as a late-inning pinch-hitter.

Manager John Gibbons made the decision to start DeRosa as a way to get another right-handed bat into the lineup against Rays left-hander Matt Moore.

"DeRo had a good spring," Gibbons said. "He came in from the get-go, swinging the bat well. One thing about him, he's a steady defender as well. If he gets to it, you're out. And he gets you a good at-bat every time he's up there.

"He's on a nice little roll himself, so take advantage of those at-bats as well. Guys that hang around the game a long time because they know how to play, they know how to play in certain situations, they're not going to make mistakes. Their bodies slowed down, naturally, but you know what? You can count on him."

DeRosa entered Wednesday night with two homers and a total of four hits in his previous eight at-bats. One of those home runs came during a key pinch-hit situation on Monday night that helped sparked Toronto's come-from-behind victory after the club trailed by seven runs.

The 38-year-old DeRosa is hitting .220 (9-for-41) with three homers and 11 RBIs in 18 games.

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.