Hill, 26, missed most of the 2008 season due to post-concussion syndrome -- the result of an on-field collision with former Toronto shortstop David Eckstein on May 29. Hill suffered from dizzy spells and headaches months after being struck on the side of the head, but has since been cleared to proceed with his normal offseason routine.
Earlier this week, Hill was optimistic that he'd be back at full strength in time for Spring Training.
"I've played baseball my whole life, so this is the longest break I've ever had," Hill said. "If anything, I'm even more excited to get back on the field now than ever, just because I have missed an extended period of time. I don't see any reason why I wouldn't be ready for Spring Training."
Hill finished the season hitting .263 with two home runs and 20 RBIs in the 55 games he played. In 2007, Hill hit .291 with 17 homers, 47 doubles and 78 RBIs in 160 games for the Jays, who signed him to a four-year extension worth $12 million that includes club options that could keep him in the fold through 2014.
Janssen was sidelined in March with a torn labrum in his right shoulder and required season-ending surgery. The 27-year-old pitcher has resumed throwing and is expected to compete for a job in Toronto's rotation or bullpen this coming spring. In 2007, Janssen served as the Jays' setup man and finished with a 2.35 ERA and 24 holds in 70 games.
Machi, 25, spent the past two seasons with Double-A New Hampshire in Toronto's farm system. In 2008, the right-hander went 2-6 with a 4.65 ERA in 21 games, including nine starts. By releasing Machi and activating Hill and Janssen, the Blue Jays' 40-man roster has reached capacity.
Jordan Bastian is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.