Tazawa's Fastball Couldn't Heat Up in Humid Texas Battle With 94 strikeouts in 109 1/3 minor-league innings this season, it’s safe to say that recent Red Sox call-up Junichi Tazawa packs some pitching punch.

On Sunday afternoon in Texas, however, Tazawa was unable to strike out any Rangers batters as he gave up 10 hits and three walks while getting six ground-ball outs and 12 fly outs before departing in the sixth after 97 pitches.

Although he’s just a rookie, failing to strike out any Rangers batters raises some red flags: This is the same Texas lineup that had struck out a league-most 925 times heading into the contest. According to manager Terry Francona, Tazawa’s problems came from a weak fastball — but while his heater was flat, his competitiveness stayed high despite the Texas heat and the 10 hits allowed.

“As we’ve come to see in his young career, he’ll battle, he won’t give in,” Francona told NESN’s Heidi Watney after the loss.

“He didn’t have his best fastball,” Francona continued. “He threw some good splits and on a hot day, it was hard work but he never gave in through 10 hits, and that’s a lot.”

Check out the exclusive NESN.com video below for the complete interview: