Glasnow is expected to make his first start for the Indians on Saturday night at Indianapolis' Victory Field against Charlotte.
"We are pleased with Tyler's development and believe he is ready for the next set of challenges in his career," said Pirates general manager Neal Huntington.
Glasnow is in line to make eight starts for the Indians, whose regular-season schedule ends on Labor Day, Sept. 7. Gerrit Cole made a total of 13 Triple-A starts prior to his mid-June 2013 big league debut.
Altoona manager Tom Prince has regularly been filling Bucs skipper Clint Hurdle's ears waxing about Glasnow's talents and progression.
"He continues to develop," said Hurdle, launching into a lengthy dissertation of Glasnow's virtues. "The use of secondary pitches in offensive counts. The fastball command improvement -- top to bottom, in and out. The ability to control the running game -- hold, step off, throw over, slide step.
"Reading swings, game-planning with the catcher -- it's all part of his overall development. The velocity has been firm. The stuff plays. The strikeouts-to-walks [ratio] really jumped out for Tom."
Glasnow has matured, both as a pitcher and as a person, remarkably since being the Bucs' fifth-round Draft choice in 2011. In the last season-and-a-half, including last year's stint in the Arizona Fall League, he has allowed only five home runs in a total of 212 innings.
"There's a cliche we use in this game: 'The ball comes out of his hand good.' It comes out of [Glasnow's] hand better than good," Hurdle said, again relaying Prince's enthusiastic impressions. "It's easy to get excited about some of our players. I think everyone Glasnow has gone through, there's been some excitement in their voice when they spoke of him."
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer and on his podcast. This story was not subject to the approval of Major League Baseball or its clubs.