The Giants announced that Snell was placed on the 15-day injured list with a left adductor strain, retroactive to April 23, at 9:45 a.m. on Wednesday, three hours before Snell was set to start against the New York Mets.
After signing a two-year, $62 million deal with the Giants on March 19 and missing the first 10 games to get back into playing shape, Snell has struggled in his first three starts with the Giants.
Snell has lost all three games, allowing 15 earned runs in 11.2 innings pitched with 12 strikeouts and five walks.
The Giants called up Landon Roupp to take Snell's spot. Ryan Walker was announced as Wednesday's starting pitcher in what will undoubtedly be a bullpen game for the Giants.