Lorenzen, 31, was a first-time All-Star this season, starting 18 games for Detroit while compiling a 3.58 ERA. The nine-year veteran will be joining his third team in three seasons as he signed with Detroit this year after playing for the Angels in 2022. He has a career 4.02 ERA as both a starter and reliever.
"We appreciate Tigers fans and the city and the staff here," Lorenzen said before leaving the visiting team's clubhouse in Pittsburgh, where Detroit plays on Tuesday night. "They followed through on their promise for me: 'You're gonna come here, we're gonna make you better.' They definitely did that. I told [general manager] Scott [Harris] on the phone, 'You followed through, and I appreciate that.'"
The Phillies rank 12th in starter's ERA and could use an innings-eater after making it to the World Series last year. Both Aaron Nola and Zack Wheeler have logged a lot of innings over the past two seasons at the top Philadelphia's rotation.
Second baseman prospect Hao-Yu Lee is going to Detroit in the deal, Philadelphia's No. 5 prospect, according to MLB Pipeline. The Phillies signed Lee out of Taiwan in 2021. The 20-year-old second baseman has hit .283 with a .372 on-base percentage and 14 stolen bases in 64 games for High-A Jersey Shore this season.
"We like Lee's bat a great deal," said Phillies team president Dave Dombrowski, a former Tigers general manager. "Maybe he'll go over to third base, but he can really hit. He's a good, young player. It's not something we wanted to do, but sometimes you have give to get."
The Phillies are in a logjam of wild-card contenders in the National League after a slow start and should benefit from Lorenzen, who despite his 5-7 record, has 83 strikeouts and a 1.10 WHIP this season. He allowed three runs in five innings in his last start, a 6-0 loss to the Los Angeles Angels last Thursday.
The Phillies, who outlasted the Miami Marlins 3-1 Tuesday night, were tied for the No. 1 wild-card spot in the NL with the San Francisco Giants before the latter's game against the Arizona Diamondbacks.
Manager Rob Thomson told reporters, before Tuesday's game in Miami, that Lorenzen will probably start on Thursday in the series finale, and that his club will install a six-man rotation for the time being.
Later Tuesday, the Phillies shipped left-hander Bailey Falter to the Pittsburgh Pirates on Tuesday in exchange for shortstop Rodolfo Castro.
Falter, 26, is 0-7 with a 5.13 ERA across eight appearances, including seven starts, this season. He has not pitched in the major leagues since May 15, when he allowed six unearned runs on eight hits in 4 1/3 innings of a loss to the San Francisco Giants.
Castro, 24, hit .228 with six homers and 22 RBIs in 78 games with the Pirates this season. He was also playing in the minors after getting optioned to Triple-A Indianapolis on July 16.
Information from Reuters and the Associated Press was used in this report.