The Toronto Blue Jays are conducting an internal investigation into a sudden spike of positive drug tests, with six minor-leaguers disciplined over the past week by Major League Baseball for using the steroid Boldenone.

A seventh player was suspended in September when Stanozolol metabolites were found in his system, establishing a new single-season high for the club. Six minor-leaguers were suspended in 2016 – two for using a banned stimulant, one for a drug of abuse and another for refusing to take a test – meaning 13 of the team’s 31 players disciplined since baseball’s punitive drug program was introduced in 2005 have come in the past two years.

"This situation is very disappointing and disturbing to the organization; disappointing that the players made these choices, but more so disturbing that some failure of our environment allowed this to happen," said Blue Jays general manager Ross Atkins. "It is our responsibility to create an environment and culture where our players know that PED use is not condoned, and to give them resources and education to ensure that they do not make these decisions.

"As we seek to determine both how and why this happened, an internal investigation into the situation remains ongoing, and we will double down on ensuring that all our staff is properly equipped to help our players make the right choices."

All seven of the players suspended in 2017 began the season with the Blue Jays’ Dominican Summer League program, with one, right-hander Jol Concepcion, graduating to the rookie-level GCL Blue Jays, where he posted a 3.78 ERA in 33.1 innings with 28 walks and 29 strikeouts.