On Tuesday night, he moved from consistent to spectacular in a complete-game effort in a 9-0 win over the Blue Jays in which he allowed just two hits and flirted with a no-hitter through 5 1/3 innings, before yielding a single to Mike McCoy.
"[It was a] wonderful performance," Rays manager Joe Maddon said. "[He] threw mostly fastballs. He started to mix in some of the offspeed stuff later in the game, but primarily pitched with his fastball. I love when our guys do that. He was in command the entire night and definitely deserved the complete-game shutout."
By the top of the ninth, the only suspense for the crowd of 12,937 at Tropicana Field was whether Niemann would be allowed to come back out to try for the complete game. The 6-foot-9 right-hander wanted to finish what he started.
Staying in for the ninth "was big," Niemann said.
"It seems like once we get there, once we know what it feels like to get up there, it seems like it's a little more attainable each time you go out there," he said. "I felt great tonight and felt great all the way through, and again, I have to thank my defense and offense for making it easier for me."
Niemann's complete-game shutout was the third of his career. Six other pitchers in team history have two shutouts in Rays uniforms: Matt Garza, James Shields, Bobby Witt, Albie Lopez, Joe Kennedy and Rolando Arrojo.
Niemann collected his 10th quality start in 12 outings this season while picking up his sixth win against no losses.
"I thought maybe he didn't get his breaking ball over like he'd like to until probably the end of the game," Blue Jays manager Cito Gaston said. "But he seemed to get his cutter over a little bit and his fastball. He pitched a great game for them."
By winning the first game of their six-game homestand, the Rays improved their Major League-best record to 38-20 while winning their second consecutive game. The victory also kept Tampa Bay in first place in the American League East by two games over the second-place Yankees, who defeated the Orioles, 12-7, on Tuesday night.
While Niemann decorated the scoreboard with zeroes, the Rays' offense came to life, scoring nine runs on 12 hits, with Carlos Pena driving in five runs on the night.
Maddon had talked on Sunday about his options for trying to help Pena snap out of a season-long slump.
A week earlier, Maddon had benched the struggling B.J. Upton for two games, and Tampa Bay's center fielder had returned a new man. But Maddon noted he had a hard time arriving at that solution for Upton since he's a weapon on defense. Same thing with Pena, so Maddon noted he would think about Pena on Monday's off-day, perhaps while he took a bike ride along Tampa's Bayshore Boulevard.
Turns out Maddon never had to burden his mind with such decisions on his day off as Pena homered in Sunday's 9-5 win over Texas, giving him his first home run since May 24, and making Maddon's decision to start Pena on Tuesday night an easy one. And Pena responded by fueling Tuesday night's offense with his bat.
Pena got Tampa Bay started in the fourth inning when he hit his 10th home run of the season on a 1-0 pitch from Brian Tallet to give the Rays a 1-0 lead.
Pena then added a grand slam off Rommie Lewis in Tampa Bay's seven-run fifth to put the hosts up 8-0.
"It just feels good to contribute with the bat," Pena said. "That's the way I have fun. As a kid, you always want to make sure you hit the ball hard, and when it actually happens in real life, I can't deny that it's a lot of fun."
Willy Aybar added to that fun when the fans at Tropicana Field urged Pena to make a curtain call. Playing the role of the imposter, Aybar moved to the top step of the dugout and tipped his helmet.
"Willy's so funny, he told me, 'If you're not going to go out there, I'm going to go,'" Pena said. "I told him, 'Hey man, at least let me get a cup of water before I go out there.' He's hilarious. He keeps us loose here."
Pena now has seven career grand slams and four as a Ray -- tying Ben Zobrist's club mark. The first baseman has three home runs in his past two games. Coincidentally, his five RBIs Tuesday followed John Jaso's five-RBI performance on Sunday.
"We finally got some runs [at Tropicana Field] and got on top and stayed on top," Maddon said.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.