“Baseball is 90% mental. The other half is physical.”

Yogi Berra’s famous remark is not only one of the most iconic baseball quotes of all time, but it’s actually true — even if the math doesn’t check out.

Baseball is an extremely cerebral game and for the greatest athletes in the sport, sometimes the best adjustments can come in the brain and not from any physical mechanics.

That’s a big part of what has led to Ryan Tepera’s success out of the Cubs bullpen over the last few weeks.

The veteran right-hander worked a perfect 7th inning during Saturday’s Cubs win. He has surrendered just 1 run in 14.2 innings this month and has not walked a batter while striking out 19.

.@RTepera in his last 10 games:

0.00 ERA, 0.10 WHIP, 16 K 🔥 pic.twitter.com/hPpWEt7rUU

— Marquee Sports Network (@WatchMarquee) May 29, 2021

On the season, Tepera has 8 holds, a 2.55 ERA and a 0.69 WHIP.

The Cubs bullpen just completed the longest stretch without an earned run in franchise history (38.1 innings) and Tepera has been a gigantic part of that success.

That includes the bases loaded Houdini acts — Thursday in Pittsburgh and an incredible performance Sunday in St. Louis.

Tepera entered into a 2-on, 0-out situation in the 7th inning against the Cardinals and committed a throwing error to load the bases. After a forceout at home and a foul out, Tepera struck out Nolan Arenado to escape the jam.

It was a huge moment in a game between the top two teams in the division in front of an expanded crowd at Busch Stadium with relaxed capacity restrictions.

“I tell you what — the other day in St. Louis was a lot of fun,” Tepera said. “We hadn’t had that kind of atmosphere in a long time. It’s probably been a year-and-a-half since we had that kind of crowd noise. You almost forget what it’s like to pitch in the big leagues.

“That was a lot, a lot of fun. It’s just a lot of fun right now. I don’t know, I’m in such a good place that it’s kind of hard to talk about it.”

If that doesn’t sum up what kind of run Tepera is on, I’m not sure what would.

He told his manager the same thing during a conversation in the outfield grass before a recent Cubs game.

“He said it feels like he’s starting to get locked in and his words to me were: ‘it’s starting to be fun,’” David Ross said. “When baseball’s fun, that means you feel comfortable and able to go out there and compete to the best of your ability.

“That’s what we love about this game — we love success and to be out there and either get guys out or get hits and play baseball at a high level. That’s when this game’s really fun.”

The 33-year-old was a big part of the Cubs bullpen last season but then hit free agency over the winter. With Rowan Wick’s intercostal strain still affecting him early in spring training, the Cubs sought veteran relief help on the open market and officially brought Tepera back on March 2.

He didn’t get off to the start he wanted in the 2021 season but he’s been as reliable as they come for Ross over the last month.

Thursday in Pittsburgh marked his first save of the season, but the irony of the moment was not lost on him. Ross tasked Tepera with closing out a game against the Pirates at Wrigley Field on May 7 but the veteran reliever was unable to get the job done and Rex Brothers had to come in to finish it off.

“That night was when I was really like, ‘man I gotta change something,'” Tepera said. “I had been struggling with mechanics a little bit and I just wasn’t having any fun. My mindset changed after that. I think that was the biggest key and that’s when the good roll started.”

Between that mindset change and some mechanical tweaks, Tepera has been in attack mode ever since.