To make room on the roster for the three additions, the 49ers waived defensive back Don Jones, offensive lineman Jamar McGloster, and defensive lineman Blaine Woodson.
As of this post, Pettis is the only player from the 49ers' 2018 draft class who remains unsigned. General manager John Lynch expressed confidence on Wednesday that a deal would get done soon.
The 49ers Communications department provided the following information on the three newly signed players.
Flynn (6-5, 320) originally signed with the 49ers as an undrafted free agent on May 4, 2017. He was waived by San Francisco on September 2, 2017, and signed to the team's practice squad the following day. Flynn was placed on the Practice Squad Injured Reserve List on November 13, 2017, where he spent the remainder of the season.
Sutton (6-1, 290) was originally drafted by the Chicago Bears in the third round (82nd overall) of the 2014 NFL Draft. In three seasons with the Bears (2014-16), he appeared in 36 games (18 starts) and registered 82 tackles and seven passes defensed. Following his release from the Bears on May 11, 2017, he signed with the Minnesota Vikings on May 17, 2017, and was later released on September 2, 2017.
Thornton (6-4, 290) originally signed with the Philadelphia Eagles as an undrafted free agent on July 26, 2011. Throughout his seven NFL seasons with the Eagles (2011-15), Dallas Cowboys (2016) and Buffalo Bills (2017), he has appeared in 89 games (48 starts) and registered 278 tackles, 7.5 sacks, six passes defensed, four fumble recoveries and two forced fumbles. He has also appeared in three career postseason contests (one start) and added six tackles. After spending training camp with the Cowboys in 2017, he was released from the team on September 3, 2017. He then signed with the Bills where he appeared in 15 regular season games (three starts) finishing the season with 27 tackles and two sacks. He also appeared in Buffalo's one postseason game.
The following information was also provided on the three players who were waived.
Jones (5-11, 195) originally signed with the 49ers on March 10, 2017. He was placed on the Injured Reserve List on September 2, 2017, where he spent the entire season. A five-year veteran, he has played in 56 games and registered 37 special teams tackles and one forced fumble on special teams. In 2016, he played in nine games for the Houston Texans and tied for the team lead with 11 special teams tackles. McGloster (6-7, 309) and Woodson (6-2, 280) each signed with the team as undrafted rookie free agents this past offseason.