Mastroianni originally injured the ankle in spring training. He had made the big-league roster and was preparing to head north, but he fouled a ball off his ankle on March 28. He came north and worked to get back on the field, which he did for eight games, and then reportedly aggravated the injury going for a fly ball in left field.
Mastroianni tried to play through it, but the team shut him down, eventually putting him in an immobilizing boot to keep him from turning a stress reaction into stress fracture. The boot was removed this last weekend but his ankle didn't respond as hoped. The team ordered further tests that revealed a bone chip in his ankle, so Mastroianni is scheduled for surgery on May 22.
"In some people, this doesn't affect them at all. But with him, (the team's doctors) said (the chip) was close to the ligament," Twins assistant general manager Rob Antony said.
The doctors decided to do an arthroscopic procedure that will grab the chip and reattach it to the bone.
"Optimistically, (we) hope he will be back on the field in six weeks (doing) rehab."
It has been a tough season for Mastroianni, and it will get tougher for him before it gets better. The surgery will put him out for a while and then, since he has missed so much time, he will be out longer with a rehab, well into July.
"All I know is it's been two months," Mastroianni told the Pioneer Press. "I've missed the first third of the season pretty much with nine at-bats. Whatever is going to get me healthy and get me able to play and help us win baseball games, I'm down for that. I'm good with that."
The Twins outfield has gone though much transition this season -- a slow start by Aaron Hicks, injury and illness, the call-up of Oswaldo Arcia -- so had he been healthy, Mastroianni would have had a chance to perform.
Antony wouldn't say whether the Twins, who fell to the Braves 5-1 Monday, will place Mastroianni on the 60-day DL and call up a player to replace him but it is an option. He intimated the Twins outfield has gone along without him to this point, and they could continue to do so until Mastroianni returns. That's what Mastroianni is likely hoping for.
"It's extremely frustrating," Mastroianni said, "but it'll be nice to have something done so there'll be light at the end of the tunnel and I can try to salvage the second half of the season."
NEXT: Twins (Mike Pelfrey, 3-4, 6.57) at Braves (Tim Hudson, 4-3, 5.12)
RHP Kevin Correia struggled with location on Monday. The result was a four-inning effort, his shortest of the year. He allowed five runs, the most allowed in his nine starts, and he failed to strike out a batter for the first time this season. Correia had been 3-1 with a 2.35 ERA over his previous four starts against the Braves.
RHP Mike Pelfrey (3-4, 6.57) will be making his 16th career start against Atlanta and is looking to snap a four-start losing streak against the Braves. Pelfrey is 4-9 with a 5.65 ERA against Atlanta. Pelfrey gave up five runs on eight hits, two of them home runs, over four innings in his last start, a loss to the White Sox.
LHP Caleb Thielbar was recalled from Class AAA Rochester when LHP Pedro Hernandez was sent down. Thielbar, who signed as a minor-league free agent in August 2011, had made 17 relief appearances for the Red Wings and posted a 3.76 ERA, with 34 strikeouts in 26.1 innings. He made his major league debut on Monday with two scoreless innings, striking out three. Manager Ron Gardenhire said, "He threw the ball well. That was a big couple innings for us."
OF Josh Willingham is 2-for-13 over his last four games, but had a solo homer on Monday night to break up a shutout. Willingham has to face nemesis Tim Hudson on Tuesday. Willingham is 1-for-20 with seven strikeouts in his career against the right-hander. Manager Ron Gardenhire said, "Let's hope that gets him going. He's a big part of our lineup."
1B Justin Morneau pulled his average up to .304 with his 2-for-4 effort on Monday. During 18 games in May, Morneau is batting .364 (27-for-74). He has hit safely in 15 of the last 16 games.
LHP Pedro Hernandez was optioned to Rochester when the Twins recalled LHP Caleb Thielbar. Hernandez allowed three runs on nine hits over 4.1 innings in his last outing Sunday against Boston. He's 2-1 with a 5.85 ERA for the Twins this year.
"He was just out of whack. They ambushed him early. Every time he made a mistake they banged it."—Manager Ron Gardenhire, regarding starter Kevin Correia, who lost for the third time in four starts as the Twins fell to the Braves 5-1 Monday. Correia lasted only four innings, the first time this season he had failed to pitch five innings. He gave up a season-high five runs on eight hits.
RHP Cole De Vries (forearm strain) went on the 15-day disabled list retroactive to March 30. He pitched in extended spring training April 25 and April 30. He began a rehabilitation assignment May 5 with Class A Fort Myers. He made his third rehab start with Triple-A Rochester on May 15. He was reinstated from his rehab assignment May 19 and optioned to Triple-A Rochester.
OF Darin Mastroianni (stress reaction in left ankle) went on the 15-day disabled list retroactive to April 16. His walking boot was removed over the May 11-12 weekend. He felt discomfort when testing foot in drills May 14. Mastroianni is going to have surgery on May 22. His stress reaction has healed, but not perfectly, according to assistant general manager Rob Antony. The early prognosis is the team "optimistically hopes he will be back on the field in six weeks," Antony said. At that time, Mastroianni would go through a rehab stint.
RHP Tim Wood (shoulder) went on the 15-day disabled list retroactive to March 24. He had his rehab assignment rescinded May 9. He underwent an MRI on his shoulder May 15 in Rochester, N.Y.
C Drew Butera (broken left pinkie) was hurt in his first at-bat of the season for Triple-A Rochester on April 5. He has reported to Fort Myers to begin rehab.
RHP Nick Blackburn (right elbow surgery in October 2012; right wrist surgery in January 2013) had begun playing catch as of mid-April. He is not on the disabled list because he was re-signed to a minor league contract.
LHP Raphael Perez (left shoulder surgery in September 2012) threw live batting practice April 11 for the first time since becoming a member of the Twins organization. He isn't on the disabled list, as he signed a minor league contract with Minnesota in February.
RHP Vance Worley
RHP Kevin Correia
RHP Mike Pelfrey
LHP Scott Diamond
LHP Glen Perkins (closer)
RHP Jared Burton
LHP Brian Duensing
RHP Casey Fien
RHP Anthony Swarzak
RHP Ryan Pressly
RHP Josh Roenicke
LHP Caleb Thielbar
DH Ryan Doumit
1B Justin Morneau
2B Brian Dozier
SS Pedro Florimon
3B Trevor Plouffe
INF/OF Jamey Carroll
INF Eduardo Escobar
LF Josh Willingham
CF Aaron Hicks
RF Chris Parmelee
OF Wilkin Ramirez
OF Oswaldo Arcia