Porzio, 30, pitched in 32 games for the Sox last season, recording a 4.81 ERA and a 2-2 record in 43 innings.
In 17 games -- 16 of which were starts -- with triple-A Charlotte, Porzio is 7-4 with 4.31 ERA in 96 innings. Porzio leads the Knights in strikeouts with 87 and has just 33 walks. However, he has given up 92 hits, which is second most on the team next to Brian Cooper.
The 25-year-old Wright, who didn't make the 25-man roster out of spring training because of a shoulder injury, is 0-4 in 11 starts with the Sox this season.
Wright led the Sox in strikeouts last season with 136 and was second in both wins (14) and innings pitched (196.1) next to Mark Buehrle (19, 239).
According to manager Jerry Manuel, the move was made strictly to help a tired pen and give Wright extra starts in Charlotte. Wright is expected to be back up in a couple weeks.