© 2014 MLB Advanced Media, L.P. All rights reserved.

6/12/2014 8:48 P.M. ET

Promotion brings top prospect closer to Blue Jays

BALTIMORE -- Top Blue Jays prospect Aaron Sanchez is one step away from the Majors.

Toronto moved the starting pitcher up from Double-A New Hampshire to Triple-A Buffalo on Thursday to bring MLB.com's No. 19 prospect in baseball, and the No. 1 prospect in the Blue Jays organization, tantalizingly close to the highest level.

Sanchez had not been dominant for the Fisher Cats, but his 3.82 ERA came with good enough stuff -- and enough quality outings -- to warrant a move.

"It's been mixed," Toronto manager John Gibbons said. "He's been really good, and there's been a couple outings when he's struggled."

Sanchez's biggest weakness has been his control. In 66 innings at Double-A, the righty had struck out 57 to 40 walks.

The command is not something that concerns Gibbons too much, though. Sanchez relies heavily on a darting fastball that sometimes moves so much, Gibbons said, that it can be hard to control.

But that also helps him get ground balls with runners on base that force double plays.

"He may be one of those guys his whole career -- he walks guys, but that doesn't mean he can't pitch at this level and be very good," Gibbons said.

Sanchez was part of a Blue Jays Draft class in 2010 that featured four highly touted high school pitchers in the first 80 picks. Two of the other three -- Noah Syndergaard and Justin Nicolino -- have since been traded.

Now Sanchez is the most valuable asset in the Blue Jays organization and could be the centerpiece of a potential Trade Deadline deal.

"He's highly thought of in the baseball world -- not only in our organization," Gibbons said. "So I'm sure a lot of teams would want him, just like we want him."

But Sanchez could also help Toronto this year with his own pitching.

There is no immediate timetable for Sanchez's arrival in the Majors, and, as of now, the organization isn't doing anything to manage his innings in anticipation of a late-season callup, but that doesn't mean he will not make a big league appearance in 2014.

"If there's a need and the organization feels he's ready," Gibbons said, "why not him?"

Mastroianni excited to join team in contention

BALTIMORE -- As a player who makes his living with his legs, Darin Mastroianni knows that two ankle surgeries and an extended stint on the disabled list a year ago have not helped his reputation.

The first surgery came at the start of the 2013 season to repair his left ankle after he fouled a pitch off of his shin during Spring Training and experienced a stress reaction. The next came at the end of that season, when a surgical piece placed in the ankle during the surgery had to be removed.

"I don't think anybody really trusted that I was healthy," the outfielder said. "I could've easily sat on the DL all year. I wanted to fight my way back, and I did."

Mastroianni began 2014 with the Twins, but he was designated for assignment after playing in just seven games. The Blue Jays claimed him off waivers and sent him to Triple-A Buffalo, where he batted .290 with 14 steals and an on-base percentage of .376 before being called up to the Majors on Wednesday.

"If I had to pick a team, I don't think Toronto would've been first on my list with the depth of outfielders they have here," Mastroianni said.

Mastroianni was not in the lineup on Thursday against the Orioles in Baltimore, but manager John Gibbons planned to use him in a similar way as outfielder Kevin Pillar was before being sent down on Wednesday.

"He'll come in and face some lefties for [outfielder Anthony] Gose, that kind of thing," Gibbons said. "He can pinch-run, do a lot of those things. He'll do a lot of what Pillar was doing."

This is Mastroianni's second stint with the Blue Jays. His first came in 2011, when he made his MLB debut for a team that finished fourth in the AL East.

Most of the faces Mastroianni encountered in the clubhouse were different -- Jose Bautista and first baseman Adam Lind were some of the few he knew from the last time around -- but the bigger change for him will be playing for a first-place team for the time in his career.

"It's exciting for me; I've always felt my role on a team was to help teams win," Mastroianni said. "When you're in first place by five games, the pressure's a little bit higher for you."

Rasmus begins rehab stint with Buffalo

BALTIMORE -- Colby Rasmus' rehab began on Thursday with Triple-A Buffalo. He is scheduled to play for the Bisons the next three days, and then the Blue Jays will evaluate him.

"He'll DH tonight, five innings in the field tomorrow, and then DH," Toronto manager John Gibbons said. "Then we'll see where he's at."

Rasmus, who went 1-for-3 with a walk Thursday evening, has been on the disabled list since May 15 with right hamstring tightness. Prior to the injury, the outfielder was batting .222 with nine home runs. Buffalo is playing a four-game series at Toledo from Thursday until Sunday.

Outfielder Anthony Gose has taken Rasmus' place in center during the absence of the left-handed hitter.

Although Toronto has laid out only a three-day plan for Rasmus, he most likely is not in line to join the Major League club by Sunday.

"We'll see how his leg feels," Gibbons said. "He needs some at-bats."

David Wilson is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.