The Indians have not officially announced the move and the ballclub will need to make a subsequent transaction to add Allen to the active roster. Cleveland is scheduled to take on Baltimore on Friday in the first game of a seven-game homestand against the Orioles and Tigers.
Allen has enjoyed a rapid ascension through the farm system.
This season, the 23-year-old Allen has fashioned a 1.87 ERA in 31 games spent between Class A Carolina, Double-A Akron and Triple-A Columbus. Last year, the right-hander went 5-1 with a 1.65 ERA across four Minor League levels, ending with a stint in Double-A. Allen was drafted twice by Cleveland -- first in the 16th round in 2010 and then in the 23rd round in '11.
In 24 games for Columbus this season, Allen has 35 strikeouts and nine walks in 31 2/3 innings. At Triple-A, he has held left-handed hitters to a .133 average and righties to a .235 showing. Overall, the reliever has 53 strikeouts and nine walks and a 0.79 WHIP in 43 1/3 Minor League innings this season.
If the Indians remove a reliever from the roster to clear a spot for Allen, the most vulnerable candidate would appear to be rookie lefty Scott Barnes. In seven appearances for Cleveland this season, Barnes has posted an 8.10 ERA with 10 strikeouts and seven walks in 10 innings.