Opening Day is a special one for everyone who loves baseball. For MLB rookies who are set to make their big league debuts, it is all the more impactful.

To celebrate rookies making their major league debuts today, and for the rest of the season, MLB has added a special element to those players’ jerseys.

Those players will wear “MLB Debut” patches on their jerseys for the game. Afterward, the patches will be added to Topps rookie trading cards for those players, making for a set of incredibly significant collector’s items.

The baseball season begins on Thursday, with the Yankees hosting the Giants and Nationals hosting the Braves at 1:05 p.m. ET. Other significant matchups include the Rangers vs. Phillies and Cardinals vs. Blue Jays in the afternoon, and a primetime Astros vs. White Sox matchup on ESPN at 7 p.m. ET.