The Giants announced Posey had been activated from the seven-day concussion disabled list.
Posey was injured during San Francisco's game against the Arizona Diamondbacks on April 10 when he was hit in the helmet by an errant pitch from Taijuan Walker.
Posey had gotten off to a fast start in 2017. The four-time All-Star hit .333/.481/.571 with one home run in seven games.
Since tearing three ankle ligaments and breaking a bone in his left leg in 2011, the catcher has appeared in at least 146 games in each of the last five seasons.
In that stretch, Posey has won the 2012 MVP Award, three Silver Sluggers and one Gold Glove. Even in a "down year" in 2016, he batted .288 with 14 home runs and picked up MVP votes for the fifth straight season.
Obviously, any extended absence by Posey would be devastating to the Giants.
Despite his hot hitting, San Francisco won just three of its first eight games and is 5-9 overall this season. It's still early, and there's plenty of time to turn things around, but the Diamondbacks and Colorado Rockies are off to fast starts and the Los Angeles Dodgers boast a roster full of talent, so the Giants can't afford to continue this April swoon.
With Posey back in the fold, maybe things will start to turn around in San Francisco.