Four days before the season opener, a torrential rainstorm forced the Redskins to move practice to an off-site gymnasium.
The heavy downpour began about 20 minutes into practice and players and coaches quickly raced inside the facility.
Despite the inconvenience, Shanahan said he did not believe moving practice off-site would significantly impact the Redskins' preparations for Sunday's game against the New York Giants.
"Well, obviously you would wish we had [a practice bubble] so we could practice inside, but I thought we got a lot done," he said. "We got a chance to review all of our assignments. We got some running in, and guys are running right now. We got a lot done, no setbacks."
Shanahan said he did not want to risk injury by continuing to practice outside.
"I was just a little afraid to practice out there because it was just a little slick," he said. "I've done it a couple times when it has been slick like that and a couple guys have [suffered injuries] in the past.
"We had a little bit too much rain. I wish we could have gone out there a little bit later but I thought it was in our best interest to practice inside."
Several times last season, the Redskins were forced to practice at off-site facilities, including once at an airport hangar.
Construction is underway on an indoor practice bubble, but the work could not get underway until the team could obtain the necessary permits.
"It didn't happen as soon as we would have liked, but we have it going up and that's the main thing," Shanahan said.