Marcus Stroman was called for a pitch clock violation during the third inning of the Chicago Cubs' season-opening win over the Milwaukee Brewers on Thursday.

He's the first player to be penalized under the new rule during a regular-season game.

"It's tough, man," Stroman said. "It's tough, this pitch clock. It's a big adjustment. I don't think people really realize it. It just adds a whole other layer of thinking."

The violation was called when he took too long to deliver a 1-2 pitch to the Brewers' Christian Yelich. Stroman was checking on the Brice Turang, who was on second base.

Under the new rules, pitchers have 15 seconds to deliver a pitch with the bases empty and 20 seconds if a runner is on base. The penalty for a pitcher running out of time is an automatic ball.

By day's end, there were 14 pitch-clock violations on Thursday: eight by pitchers, four by batters, one by a baserunner and one by a catcher.