Johnson signed a one-year deal with the Rockies on Tuesday, Thomas Harding of MLB.com reports.
Johnson's arrival in Colorado makes him immediately one of the team's most interesting relievers. Since his return from a stint in Japan, he's recorded a 3.39 ERA across three seasons, with his 32.2 percent strikeout rate offsetting an 11.3 percent walk rate. Elbow tendonitis limited him to just 14.1 innings last year, however, and he's heading into his age-32 season, so his health issues are unlikely to suddenly evaporate. Still, his strikeout stuff makes him a good fit for a high-leverage role, and he'll get a good chance to record his first career save next season if healthy. If Daniel Bard struggles or gets hurt, Johnson could find himself pitching in the ninth inning on a regular basis.