Since being activated from the MLB Family Medical Emergency List on June 3, Tolleson has a 1.00 ERA through nine innings and has held opponents to a .107 average. Before the leave, Tolleson had a 10.12 ERA through 16 innings and was removed from the closer role May 18. He's been able to lower his ERA to 6.84.
"I feel good. The only things is, is that I'm getting hit less, there's nothing else to it," he said. "I've tweaked a few things here and there, but it was more about me just getting through it and throwing aggressively."
Rangers manager Jeff Banister's explanation was as simple as Tolleson's.
"Strikes, quality strikes," he said. "I know there was a little talk about the rushing of his delivery, I think he's calmed that down. It comes down to quality strikes."
As the primary closer last season, Tolleson racked up 35 saves with a 2.99 ERA. His ability to find the strike zone in June has him resembling the pitcher he was in 2015.
"When a pitcher can put a ball where he wants to, he's got a much better chance for greater success," Banister said.
Tolleson has been especially effective the past two weeks, picking up two wins over his past four outings, and throwing six scoreless innings in the process. One of those wins came Monday against the Orioles when he threw 1 2/3 innings of scoreless relief, allowing just two hits.
He also threw a perfect ninth in Saturday's 10-3 win over the Red Sox.
"Confidence, whether you know it's there or not, probably has something to do with it," Tolleson said. "When you go out there time and time again and you have success, you expect those results."
Ryan Posner is a reporter for MLB.com based in Arlington. This story was not subject to the approval of Major League Baseball or its clubs.