Full story on all of today's roster moves on CSNwashington.com
The trade of Gonzalez leaves the Nationals' spring roster at 25 and means veteran Alex Cora has made the club as a reserve infielder.
General manager Mike Rizzo had received interest from several teams in Gonzalez, who hit .377 this spring while playing all four infield positions. Because the 26-year-old was out of options, the Nationals couldn't have sent him to the minors without first exposing him to waivers.
Club officials had already decided they wanted to keep Cora, a 13-year veteran who hit only .210 last season with the New York Mets and Texas Rangers but hit .359 this spring and took on a leadership role in the clubhouse.
Davis, 24, went 14-3 with a 3.52 ERA and 133 strikeouts in 27 combined starts last season between the Padres' Class A, AA and AAA affiliates. He was San Diego's 13th round pick in the 2008 draft out of Stanford, where he was a teammate of Nationals reliever Drew Storen.