Left-hander Yusei Kikuchi is returning to action on Friday, beginning a rehab assignment at triple-A Buffalo with the Bisons.

Kikuchi, 31, landed on the 15-day injured list with a neck strain on July 7. The 6-foot lefty resumed throwing prior to the All-Star break, throwing a bullpen session in Toronto at the Rogers Centre.

The Blue Jays signed Kikuchi to a three-year, $36-million contract over the off-season, unfortunately, he’s struggled mightily this season. In 16 starts, he’s posted a miserable 5.12 ERA, 6.23 xERA, 5.80 FIP and a career-worst -0.6 fWAR rating across 65.0 innings.

Before being placed on the IL, the former Seattle Mariner allowed four runs on two hits and five walks in just 2.1 innings versus the Oakland Athletics on Jul. 5. In his absence, right-hander Max Castillo has filled in as a starter, surrendering six runs, four earned, eight hits and one walk while recording four strikeouts through 7.1 innings in two starts.

Castillo is expected to remain a starter until Kikuchi returns from the IL. Afterwards, assuming he doesn’t remain in the starting rotation, the 23-year-old will likely shift to the bullpen and serve as a multi-inning reliever.

Toronto is scheduled to begin its second half with a three-game series in Boston versus the Red Sox.