Former first-round pick (2006) from the Red Sox has signed with the Bucs, according to Kevin Goldstein's Twitter. Johnson's scouting report includes "a 90-94 mph fastball, a mid-70s hard curveball, and a very good 83-84 mph changeup." But his numbers in AAA the last three years were, well, disastrous, and he's now 27. Sounds like a Neal Huntington project to me.
UPDATE by Charlie: Prepare for lots of, 'The Pirates are so cheap, they just replaced Paul Maholm with a guy with a 12.63 ERA in the minors!' As if other teams don't make minor-league signings too. That said, I'm a little mystified as to what the Pirates see here - they must love Johnson's stuff, because otherwise, signing a guy who somehow allowed seven homers in 20.2 Class AAA innings last year wouldn't make a whole lot of sense, unless they needed someone to throw batting practice.
Also, Aaron Thompson signed with the Twins.