The reported agreement is for one year and around $4.5 million, according to Jim Owczarski of the Cincinnati Enquirer.
According to Darlington, Smith was close to choosing the Buffalo Bills:
Smith's career has been defined by injuries. He was drafted by the Bengals with the sixth overall pick in 2009 with the assumption he would be a dominant force up front for years.
It wasn't until Smith's fourth season in 2012 when he was able to play all 16 games. He was able to do it again in 2013 but has missed 21 games over the past three seasons.
The Minnesota Vikings took a chance on Smith with a one-year deal last season. The 30-year-old started the first four games in 2016 before a triceps injury landed him on injured reserve.
Even when Smith was on the field for the Vikings, his performance was lacking. Through the four games he played, Chris Tomasson of the St. Paul-Pioneer Press noted Pro Football Focus rated him as the 69th-best offensive tackle out of 75 total players.
The Bengals know Smith better than any NFL team after drafting him and giving him seven years to blossom into a star.
There were certainly flashes that Smith was hitting his stride, particularly in that 2012 season, but it has really been undone over the last three years by an inability to stay on the field.
If the Bengals are able to take advantage of Smith in spots, without asking him to carry the load as an every-down player, he can rebuild his value to the point where teams will feel more comfortable signing him to be a starter in 2018.
The Bengals may not have the luxury of playing Smith part-time since they need a permanent right tackle after Andrew Whitworth signed with the Los Angeles Rams. It's asking a lot of him to stay healthy for 16 games, but at least the team knows what he provides at his best.