On Tuesday night, he didn't give the Boston Red Sox many.
Diamond allowed three hits in seven shutout innings, Ryan Doumit hit his first homer of the season and the Twins beat the Red Sox 6-1.
Diamond said he still felt strong when he left the game but understands the cautious approach less than five months after the operation.
"This is only my (fifth) start after surgery," he said, "so I feel it was a smart play."
Diamond (3-2) is having a strong season after a rookie year in which he went 12-7 with a 3.54 ERA. He's allowed three or fewer runs in four of his five outings.
On Tuesday, he retired his last 15 batters, didn't allow a runner past second base, struck out two and walked none.
"Diamond was great for us," Twins manager Ron Gardenhire said, but "coming off the elbow thing, we're really a little leery of" letting him throw too many pitches.
He threw 96 against Boston after tossing 78, 97, 97 and 88 in his other starts.
"Everything's kind of been getting back in sync," Diamond said. "That's the focus now, just continue to build and get stronger."
His approach to the game hasn't changed even if he's not pitching as long as he'd like. He still prepares intensely and throws aggressively.
"I might as well have taken a rocking chair out there. He makes it real easy," Doumit, his catcher, said. "He's one of the most prepared pitchers I've ever been around."
David Ortiz got one of the hits off Diamond, a leadoff single in the second that stretched his hitting streak to 27 games, a run that began before he sustained a season-ending injury in August. He has at least one hit in all 15 games he's played this season.
Ryan Dempster (2-3) pitched well for Boston and left trailing 2-0 in the top of the eighth after third baseman Pedro Ciriaco made errors on the first two batters, putting runners at first and third. That led to four runs, three of them unearned, as the Twins took a 6-0 lead.
The Red Sox entered the game with the best record in the majors, but have scored just 11 runs while losing four of their past five games.
They also lost two players after they collided chasing a foul pop by Chris Parmelee in the fifth near the low wall about halfway between home plate and third base.
Third baseman Will Middlebrooks caught it, but catcher David Ross slid into him, forcing his back to hit the wall. Ross left later in the fifth with a left thigh contusion and Middlebrooks was replaced by Ciriaco to start the seventh because of pain in his right side.
Ross is listed day to day, while Middlebrooks said he could have stayed in the game but will have X-rays and a CT scan, Boston manager John Farrell said.
"We don't think Will's situation is more than day to day at this point," Farrell said. "We'll certainly get a better read when the test results come back, but my thoughts haven't gone down that path yet."
Ross, whose X-rays came back negative, said he wasn't entirely certain of how he got hurt.
"It happened so fast," he said. "Everybody told me that my shinguard, as I hit the ground, it forwarded [sic] over and my knee hit the dirt pretty hard. It's right on the top of my knee.
"I jammed the top of my kneecap. The top of my kneecap is really sore. There's some swelling in there. If I wasn't a catcher, I think I'd be fine, but squatting is a little sore. I couldn't get up there in case the ball was in the dirt and [I had to] stop it from getting to the backstop. It was best to let Salty [Jarrod Saltalamacchia] get in there. Tough night."
The Twins took a 1-0 lead in the fifth on a leadoff double by Doumit and an RBI single through a drawn-in infield by Wilkin Ramirez. They made it 2-0 on Doumit's homer with one out in the seventh. It was upheld on video review after umpires ruled the ball had cleared the home run line at the top of the left field wall before a fan caught it.
"I made two mistakes and (Doumit) took advantage of both of them," Dempster said. "The way Diamond was throwing the ball and keeping us in check, you knew that eventually one run would be maybe one run too many."
It all unraveled for the Red Sox in the top of the eighth with three errors, a walk and three hits.
Ciriaco bobbled leadoff hitter Brian Dozier's grounder for his first error. The next batter, Jamey Carroll, hit the ball to the left of Ciriaco, who couldn't come up with it for his second error as Dozier took third.
"That was uncharacteristic of Pedro," Farrell said. "He has shown to be a very dependable defender."
Said Ciriaco: "I just missed those two balls. I've just got to be more ready and next time make those plays."
Craig Breslow then replaced Dempster and failed to retire any of the four batters he faced. Joe Mauer doubled in one run, Josh Willingham walked to load the bases and Justin Morneau and Trevor Plouffe followed with RBI singles.
Alex Wilson relieved Breslow and Doumit grounded to first baseman Mike Napoli, who threw home for the force out -- the first of the inning. Saltalamacchia tried to double-up Doumit, but his throw was low for an error and Napoli's return throw was too late to get Morneau.
Patty Campbell, mother of Krystle Campbell, who died in the Boston Marathon bombings, threw out a ceremonial first pitch. ... With two singles, Morneau has 1,219 in his career, passing Torii Hunter's 1,218 for eighth most in Twins history. ... Pedro Hernandez (1-0) pitches for Minnesota against Allen Webster (0-0) on Wednesday night in the third game of the four-game series ... The Red Sox placed Joel Hanrahan on the disabled list with a strained right forearm one day after their other closer, Andrew Bailey, went on the DL with a strained right biceps. Farrell said Junichi Tazawa would have filled that role if needed. ... Ortiz's streak is the longest by a Red Sox player since Manny Ramirez had a 27-game streak from July 15 to Aug. 1, 2006.
Information from ESPNBoston.com's Gordon Edes and The Associated Press was used in this report.