In brief: Donovan's successor will have a full plate. In addition to managing the 5G rollout, they will have to deal with the fact that the company continues to lose premium pay TV subscribers. AT&T's streaming offering is also a mess with no less than four services in the pipeline.

AT&T Communications on Monday revealed that CEO John Donovan plans to retire from his post on October 1. The timing of the announcement couldn't be more critical as the industry is in the middle of a major transformational period.

Donovan joined AT&T in 2008 as chief technology officer and was eventually promoted to chief strategy officer and group president before nabbing the role of CEO of AT&T Communications in July 2017.

Randall Stephenson, AT&T's chairman and CEO, said Donovan led the way in encouraging his team to continuously innovate and develop their skill sets for the future. "We greatly appreciate his many contributions to our company's success and his untiring dedication to serving customers and making our communities better," he added.

Indeed, Donovan was instrumental in helping to lay the groundwork for AT&T's 5G future but his departure comes just as the company's effort is taking root. His leadership may also be missed during this time of uncertainty as the powers that be continue to debate over whether or not to allow T-Mobile and Sprint to merge, paving the way for a fourth major carrier - Dish Network - to emerge.

AT&T said it will name Donovan's successor soon.

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