OAKLAND -- Marcus Semien played on Jackie Robinson Day for the sixth time in his career. But just because he’s experienced it before, that does not mean the significance is diminished as each year goes by.

Semien fell in love with baseball as a youth in the Bay Area. Even though he never had the opportunity to watch Robinson play, the shortstop was well aware of the impact he made April 15, 1947, when he broke baseball's color barrier as the first African-American to play in Major League Baseball.

“You want to be in the big leagues on this day,” Semien said. “The opportunity he paved out for guys like me and a lot of guys on that field, we wouldn’t have had that opportunity if it wasn’t for him stepping up.”

Semien was excited to see his No. 42 jersey sitting at his locker before Tuesday’s game against the Houston Astros and said he would even like to see the tradition trickle down to the Minor Leagues one day.

“It’s really cool to see 42s all over the field,” Semien said. “ I’m sure it’s hard for the broadcasters and announcers but we all think it’s fun. To honor a man who people are still talking about 100 years later for the hero he was, we all want to play for him.”

Bob Melvin never had the opportunity to don the No. 42 jersey as a player with the tradition not taking effect for all uniformed personnel until 2009. Now as a manager, he takes great pride in honoring Robinson’s legacy, one he knew very well growing up.

“He’s inspiring to everybody not only in baseball but in sports,” Melvin said. “As the years go on, everybody is even more aware of what he meant. On top of that, he was a really good player.

“There are certain guys throughout the course of the history of baseball that you have a better understanding of what they were all about. Even if you are not that aware about the history of baseball, you are aware of what Jackie Robinson meant. We are all proud to wear 42 today.”

Olson and Manaea take steps forward

Matt Olson took two-handed swings with a fungo bat before Tuesday’s game. It was his first time taking any type of swing with both hands since undergoing surgery on his right hand, which involved a right hamate excision, on March 22. The next step for Olson is to take swings off a tee with a regular bat.

Injuries of this kind usually require around six to eight weeks for a full recovery, but each case is different. The A’s have not placed an official timetable on a potential return for Olson, but they have been encouraged by his progress.

“I think we’re right on schedule with him,” Melvin said. “I know he’s pretty eager to face some pitching but it’s going to be a little more time before we do that.”

Olson is coming off a first full season in which he hit 29 home runs and won his first career Gold Glove at first base after playing in all 162 games in 2018.

Sean Manaea extended the distance on his throwing program from 90 to 120 feet Monday. The left-hander will continue to throw from that distance for the next couple of weeks before advancing to long-toss and bullpen sessions.

After undergoing surgery on his left shoulder last September, Manaea said he has marked the All-Star break as a target date for his return to the mound.