Play was suspended for more than 30 minutes as Buxton was stabilized on a stretcher and carried into an ambulance at New Britain Stadium. Buxton laid on the ground for several minutes and did not appear to be moving. Kvasnicka left the field under his own power but went with Buxton to the hospital.
Twins general manager Terry Ryan was at the game and accompanied Buxton in the ambulance.
"I don't know if I've seen a collision that severe in recent memory," said Ryan. "But Byron Buxton's fine. He's alert. He has a concussion, so we'll have to take the normal procedure and protocol for concussion symptoms. He'll certainly be watched."
Ryan said Buxton was unconscious for 10 minutes but had no broken bones, neck or shoulder injuries. RockCats manager Jeff Smith said Buxton returned to the team after the game.
"It could have been a lot worse, we all know after watching that thing," said Ryan. "So we're grateful for just the concussion."
Buxton's season has already been marred by injuries. He sprained his left wrist in March, aggravated it in May while sliding into third base and returned in July only to be hit by a pitch on his right wrist.
"It has been that type of year," Ryan said, "but he is going to be fine. He is a battler."
On Wednesday, Buxton struck out three times and threw out a runner at third before the collision.
Buxton was hitting .240/.313/.405 in 30 games for Class A Advanced Fort Myers prior to being called up. In 2013, he batted .334/.424/.520 with 55 stolen bases in 125 games.
Aaron Leibowitz is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.