Underwood, 24, is a veteran of two NFL seasons with the Jacksonville Jaguars who signed with the Patriots on Aug. 29, 2011 after being released by Jacksonville. He was released by the Patriots on Sept. 3, 2011. Underwood, 6-1, 183 pounds, originally entered the NFL as a seventh round draft choice (253rd overall) by Jacksonville in the 2009 NFL Draft out of Rutgers. After beginning his rookie season on the practice squad, he joined the 53-man roster and appeared in three games, mainly on special teams. Last season, he played in 10 games and caught eight passes for 111 yards and returned 24 kicks for 561 yards, including a career-long of 53 yards in the season-opener vs. Denver (9/12).
Haynesworth, 30, was acquired by the Patriots in a trade with the Washington Redskins in exchange for an undisclosed draft choice on July 29, 2011. He originally entered the NFL as a first round draft choice (15th overall) of the Tennessee Titans in 2002 out of Tennessee. He signed with Washington as an unrestricted free agent on Feb. 7, 2009. Haynesworth, 6-6, 350 pounds, played in six games with the Patriots and collected six total tackles and one quarterback hit. He has started in 86 of 116 games and accumulated 532 total tackles, 30.5 sacks, 20 passes defensed, seven forced fumbles and four fumble recoveries during his NFL career.
Gronkowski, 26, was originally signed by the Patriots on Sept. 7, 2011 and played in the first two games before being released on Sept. 23, 2011. He was re-signed to the Patriots on Oct. 11 and played in the last three games. Gronkowski, 6-5, 255 pounds, originally entered the NFL as a seventh-round draft pick (255th overall) of the Detroit Lions in 2009 out of Maryland. He was traded by Detroit to Denver on Sept. 4, 2010. Gronkowski was released by Denver on Sept. 3, 2011. He has played in 19 NFL games, including five with the Patriots, and has nine receptions for 65 yards in his career.
Welch, a seventh round draft pick of the Patriots in 2010 out of Vanderbilt, has had two stints on the 53-man roster after starting the season on the practice squad. Welch, 6-7, 310 pounds, played in three games with one start for the Patriots in 2011.