Byron Buxton gets a good break with no break in his hamate bone

As joyous as their comeback victory was Thursday, the best news for the Twins might have come before the game even began.

Byron Buxton left Target Field on Wednesday night having learned a new word: "hamate," a word frequently preceded by "broken," and sometimes "season-ending."

But a magnetic resonance imaging exam determined Buxton's hamate bone in his left hand is intact, and the pain he experienced a day earlier was the result of a bruise in the area. The center fielder, riding a late-season surge that has made him one of the game's most exciting players, can return once the pain subsides.

"Things are progressing pretty good. He's a little sore today, but hopefully we've dodged any major issue there," said Derek Falvey, Twins chief baseball officer. "Buck's a pretty tough kid. … Based on our reads today, we're in a good spot."

Buxton thought he was OK, too, but doubts rose in his mind as Wednesday's game with the White Sox went on. "I swung at a pitch on my first at-bat, and the bat slipped out of my hand. I felt a sharp pain but paid no attention to it, tried to play through it," he said. "My last at-bat, it was throbbing pretty good," so he informed the team's athletic trainers what he was feeling. That last at-bat was a single up the middle — "a painful hit," Buxton said. "Actually, I never heard of a hamate until last night."

The 23-year-old could be back as soon as Friday. "We're encouraged. We're kind of day-to-day," manager Paul Molitor said, relieved. "We'll see tomorrow. I'm sure he's going to be kind of anxious to swing the bat and we'll see where we're at."

Reinforcements on way

Falvey said he and General Manager Thad Levine were monitoring the waiver wire as Thursday night's deadline for transactions involving players eligible for the postseason approached, but it appeared unlikely that the Twins would make a deal. "I wouldn't peg it as a high probability at this stage," Falvey said.

But the Twins will make roster changes Friday, bringing in the first of what could be several September call-ups. Lefthanders Buddy Boshers and Nik Turley will return as the 25-man roster limit is lifted, and utility player Niko Goodrum will be added to make his major league debut.

Goodrum is an eight-season veteran of the organization, drafted in 2010. The 25-year-old has played every position but pitcher or catcher this year at Class AAA Rochester, hitting .265 with 13 home runs in 127 games.

More call-ups are expected next week, once minor league seasons end Monday, though most Twins affiliates will play in the postseason, too.

From the disabled list

• Third baseman Miguel Sano, out 10 days because of a stress reaction in his shin, is wearing a walking boot but is "continuing to progress," Falvey said. "Still some soreness in that general area." The All-Star was not at Thursday's game so he could be examined by doctors again, and the Twins have hope his condition will allow him to resume rehab work this weekend.

• Jason Castro's recovery from a concussion is largely complete and he should be off the disabled list soon, and the Twins are now unlikely to call up a catcher. "He took [batting] cage swings yesterday and felt good. He ran and felt good," Falvey said.

• Robbie Grossman (fractured thumb) has started taking some swings, though "there's still a little bit of soreness in there," Falvey said.

• Lefthander Adalberto Mejia's start for Rochester on Wednesday — three innings, no runs, two hits, four strikeouts, one walk — was "very encouraging," Molitor said. "His velocity was where it was before he had that [upper] arm injury. The plan for him is to start again next Monday."

• Hector Santiago's most recent outing for Rochester "wasn't as promising," Falvey said of the lefthander, out for nearly two months because of shoulder soreness. "We want to see him progress through another start."

• Lefthander Dietrich Enns (sore left shoulder) departed for Rochester on Thursday and will pitch two innings Friday.