SIOUX FALLS, S.D. (KELO) — Kelby Krabbenhoft and Sanford Health have agreed to part ways, Sanford announced in a news release at about 5:45 p.m. today.

Bill Gassen will replace Krabbenhoft as the president and chief executive officer of Sanford effective immediately. Gassen was the chief administrator officer for Sanford.

“Bill is the right person to lead Sanford Health through these unprecedented times because of his substantial experience with many aspects of the organization and his deep commitment to our workforce,” board chairman Brent Teiken said. “We’re extremely optimistic about having his steady hand at the wheel in partnership with our existing leadership team.”

Krabbenhoft last week wrote a letter to staff that caused a chain reaction. The letter included this statement about mask wearing during the pandemic: Masks have been a symbolic issue that frankly frustrates me.” He went on to write: “The “on-again, off-again” behavior of mask use by the general population violates every notion of serious infectious management that I was trained to adhere to, so some of this is absurd.”

Krabbenhoft’s letter triggered this response from Micah Aberson, the executive vice president of Sanford Health: “Kelby Krabbenhoft’s email was based on his own experience with COVID-19 and his personal opinions about the virus. They do not reflect the views of our health system as a whole. Sanford Health’s position is the same as it has always been – consistently wearing masks, avoiding crowds and staying home if you’re sick are critical to preventing the spread of the virus. It is important to follow CDC guidelines. We continue to be incredibly grateful to our frontline workers who are stepping up every day to take care of our patients.

Krabbenhoft’s departure is early than expected. When Sanford and Intermountain Healthcare of Utah announced a planned merger on Oct. 26, Krabbenhoft said he planned to retire in 18 months.

Krabbenhoft said in an interview today with KELOLAND’s Angela Kennecke that while he was influenced by recent events that is not the reason he is leaving Sanford at this time.

Now is the right time to leave because the health system is doing so well, Krabbenhoft said in the interview. He said he hand selected the management team and Sanford is in a strong position.

“If there was ever a time for a guy, who’s been through what I’ve been through, this is a great time to say goodbye,” Krabbenhoft said in today’s interview.

Krabbenhoft had been the CEO since 1996.

The merged Sanford and Intermountain system will employ more than 89,000 people and operate 70 hospitals. It is expected to be final in 2021.