The Mariners had hoped to let Paxton throw about three innings or 45 pitches, but replaced him with Logan Bawcom when his first inning went too long.
The 26-year-old was 3-3 with a 3.70 ERA in his first 10 outings as Seattle's No. 2 starter this season before injuring his finger.
He'll likely need at least two more Minor League starts now before being ready to rejoin the Mariners in early September.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB, read his Mariners Musings blog, and listen to his podcast.