In October 2005, Boulton was suspended for six games after elbowing Tampa Bay Lightning rookie Paul Ranger, causing a hairline fracture of the jaw and a concussion.[1] The incident occurred at the end of a 6–0 rout of the Thrashers on October 20, 2005. NHL vice-president Colin Campbell said, "It is clear Mr. Boulton's actions were careless and caused injury. There is no circumstance that can justify this type of action." Only a week earlier, Boulton had made a similar move in a game against the Toronto Maple Leafs, almost injuring Eric Lindros.
Boulton was re-signed by the Thrashers in 2008 to a two-year deal. He recorded his first career hat trick on December 18, 2010, against the New Jersey Devils. He then signed as an unrestricted free agent with the Devils for a 2-year contract worth $575,000 in the first year and $750,000 in the second, joining former Thrashers teammates Ilya Kovalchuk and Johan Hedberg.[2] After a dismal season in which the Devils did not record a single goal for with Boulton on the ice, Boulton was bought out of the final year of his contract on June 30, 2012. The next day, Boulton proceeded to sign a one-year deal with the New York Islanders.[3] He re-signed with the Islanders for the next three consecutive seasons as well, all on one-year deals.[4] Boulton is the Thrashers' all-time leader in penalty minutes with 639 penalty minutes.
After the 2016–17 season, Boulton ended his professional career, however continued his association with the Islanders in accepting a scouting role.[5]