Stassi has 13 hits and two home runs in just 73 at-bats with the Phillies this season.
The 27-year-old has spent the bulk of the season with the major-league club, but doesn't have much to show for it. Stassi hasn't made back-to-back starts since mid-May and will likely be optioned again at some point, but for now he should see infrequent opportunities as Philadelphia's backup first baseman.