Rice spent 14 seasons in the minor leagues, including three seasons in independent ball, before finally making the Mets roster out of Spring Training in 2013.
"Sure, I have a little more confidence, a sense of knowing I can pitch at this level," Rice said (Ackert). "But I feel the same going into this spring training as I have every year before."
The 31-year-old pitched in 73 games for the Mets last year, posting a 3.71 ERA and 1.353 WHIP over 51 innings (Stats). He hit the disabled list with a sports hernia in early September, which required surgery to repair.
Rice will likely be the second lefty in the bullpen, along with Josh Edgin.