Roberto Kelly, the first base coach of San Francisco Giants was struck in the back of his head during a practice session on Saturday.

Kelly was standing near second base when Buster Posey's ball hit him in the head. Kelly sustained a concussion as a result of it. Before becoming a coach, he was a professional baseball player and was a member of four playoff teams.

Kelly, however, should be available for the game on Sunday for the NL championship series if he receives a go-ahead by team doctors.

Kelly needed some help getting off the field and had to be paced on a stretcher. The Giants were practicing at the AT&T Park for their game against the St. Louis Cardinals.

After the incident on Saturday, Kelly was promptly admitted to hospital. He was discharged a little while later after a few tests were done. Dave Groeschner, the athletic trainer who accompanied him to the hospital said, "Doing better, going home. We'll let the doctors see him tomorrow."

Posey, whose ball had struck Kelly, said he was unaware of what had happened.

He said, "I saw him on the ground like everybody else, I didn't see it hit him. Anytime somebody gets hit in the head you're worried for them. He seemed to be doing all right. He was cognizant and answering questions. I think any time with a head injury, it is scary because you just can't take anything for granted with that, and you have to be really, really careful."

Kelly, who is 48 years old, has served as first base coach for the San Francisco Giants since 2008. He spent a major chunk of his playing career with the New York Yankees between 1987 and 1992. His hitting average is .290 with 124 home runs and 585 RBIs.

He has also played for several teams which include the Expos, Reds, Braves, Rangers, Twins, Dodgers and Mariners. He was also a 2-time All-Star having played as many as 1337 career games.

Prior to being promoted as first base coach for the Giants, Kelly used to manage Class-A Augusta of the Giants between 2005 and 2007. The coach emphasizes mainly on base-running and outfield defense.