The Patriots also re-signed offensive lineman Dan Connolly and signed tight end Daniel Fells and defensive end Jonathan Fanene, both free agents. They released linebacker Christian Cox.
The Lloyd signing had been reported for days. The 30-year-old receiver is two seasons removed from catching 77 passes for an NFL-best 1,448 yards and 11 touchdowns -- all career highs -- with the Denver Broncos.
He was traded Oct. 17 to St. Louis for a conditional draft pick and played 11 games for the Rams, grabbing 51 balls for 683 yards and five touchdowns.
Lloyd had 70 catches for 966 yards in 15 games overall for St. Louis and Denver last season and owns career numbers of 311 receptions for 4,784 yards and 31 touchdowns.
Connolly played 13 games for the Patriots last season, starting 11, while Fells had 19 catches for 256 yards and three TDs in 16 games for the Broncos and Fanene posted 24 tackles and 6.5 sacks in 16 games for the Cincinnati Bengals.