Parnell, 31, has dealt with significant injuries over the last two seasons, appearing in only 31 games with the Mets in that span. He is expected to compete for a back-end bullpen spot with the Tigers, who have already added Francisco Rodriguez, Mark Lowe and Justin Wilson to the mix this winter.
Parnell appeared in 30 games for the Mets last season, posting a 6.38 ERA in that span while suffering a significant drop in velocity. He was previously a very good option for New York, registering ERA marks of under 3.00 in 2010, 2012 and 2013.
Parnell has spent his entire 8-year career with the Mets, posting a lifetime 20-28 record and 3.78 ERA while saving 37 games in 329 appearances. He will try to bounce back with a strong spring training for Detroit and make the team once the season begins in April.
For a complete list of free-agent signings this winter, check out our updated free-agent tracker.