According to ESPN.com's Jamison Hensley, Bisciotti said, "It was certainly a consideration, but not one that I was inclined to make this year."
Baltimore went 9-7 this season and missed the playoffs on a tiebreaker after losing to the Cincinnati Bengals on a late, fourth-down touchdown in Week 17.
Bisciotti mentioned the Ravens bouncing back late in the season as a reason behind his decision to keep Harbaugh in the fold:
"Certainly, it was a thought. I was very proud of the way John kept fighting, held the team together when we were losing in the middle of the year. [Quarterback] Joe [Flacco] was obviously producing at substandard with his back injury and after the first couple of weeks, obviously, we were very encouraged by our defense and thought that could hold us together. We didn't perform very well in the middle of the year. I was proud of the way we fought back as a team."
Baltimore won five of its final seven games of the season, however, it was unable to hang on to a late lead against Cincinnati in Week 17 to reach the playoffs.
The Ravens have now missed the postseason in three straight years after making it in six of the previous seven seasons.
Despite the Ravens' recent struggles, Bisciotti said he isn't making a playoff-related ultimatum to Harbaugh entering 2018:
"He's under as much pressure than probably he's ever been in his life, and I expect him to keep his chin up and take his positivity and his talents and make the most of the season. I may as well replace him now if I tell him to make the playoffs or you're out of town next year. That's not the way we run business here."
In 10 seasons under Harbaugh, Baltimore is 94-66 during the regular season. It is also 10-5 across six playoff appearances, including a championship at the end of the 2012 season when it beat the San Francisco 49ers in Super Bowl XLVII.
Harbaugh is under contract through 2019.