Buchholz, 32, was the odd man out in a Boston rotation that added Chris Sale this off-season. He now finds himself sitting near the top of a lengthy depth chart for the Phillies rotation that includes Jeremy Hellickson, Aaron Nola, Zach Eflin, Jake Thompson, Ben Lively, Nick Pivetta, Mark Appel, Alec Asher, Adam Morgan and others.
The Red Sox picked up Buchholz’s 2017 option in November, but the Phillies will take on the $13.5 million.
"Clay had a very productive tenure with the Red Sox, and we look forward to seeing what he can do in a Phillies uniform," Phillies general manager Matt Klentak said in a statement. "He is a welcome addition to our young starting rotation."
Buchholz, who has spent his entire 10-year career with the Red Sox, has had some up and down years with the team. He famously became the first Red Sox rookie to throw a no-hitter when he did it back in 2007, and his best season came in 2010 when he pitched to a 2.33 ERA in 28 starts and 173.2 innings. H went 8-10 with a 4.78 ERA in a career-high 37 games (21 starts) last season.
Given Bucholz's contract, the move aligns with other transactions completed by Klentak this off-season. If he performs well he could be a potential target at the trade deadline and the Phillies may pick up a prospect or two. If he falters, the Phillies don't have to worry about being locked in to a multiyear deal.
Tobias, 24, was a 10th-round pick in 2015 and is a .301 career hitter in the minors, though there's some question as to if he can stick at second base.
To clear space on the 40-man roster for Buchholz, the Phillies designated Richie Shaffer for assignment. Shaffer was claimed off waivers by the club last week.