BALTIMORE -- Alex Meyer, rated as the top pitching prospect in the Twins' system, "couldn't get loose" while pitching for Class AAA Rochester on Saturday, a Twins official said, and was removed from the after after recording only four outs.

The move was "precautionary," Twins director of minor leagues Brad Steil said via text.

The outing was likely Meyer's final one of 2014, since the International League regular season ends on Monday. Meyer, generally limited to 80-85 pitches all season after suffering a shoulder injury in 2013, had been a candidate for promotion to the major leagues when rosters expand next month, but that's unlikely after he faced only six batters in his final start against Buffalo.

Meyer, whose fastball is normally clocked at 95 mph or above, was hitting only 90 mph during his brief start. He allowed a run in the first inning on one hit, then a walk and a double in the second before being replaced by Mark Hamburger. Meyer remained in the dugout as his teammates tried to rally from the early 3-0 deficit.

Meyer, who leads the IL in strikeouts with 152 in 130 1/3 innings, did not strike out any of the six hitters he faced. A recent strikeout binge -- 67 in his last 52 innings -- gave him a three-strikeout lead over Durham righthander Nate Karns in his attempt to become the first Twins prospect since Boof Bonser in 2005 to win the IL strikeout crown.

Meyer, acquired from Washington in exchange for center fielder Denard Span two winters ago, is the second top pitching prospect to walk off the mound early with shoulder tightness. Two weeks ago, 2013 first-round pick Kohl Stewart was removed from a game in the second inning and has not pitched since.