"Disgustingly consistent," Maddon said. "He's been the same way from the very first game. Regardless of the competition ... he has been consistent."
Shields is scheduled to start in the second game of this series with the Orioles on Wednesday, and he is closing in on becoming the third pitcher in club history to reach 200 innings in a season.
He's been strong from the start, posting a 10-8 record and a 4.09 ERA with 162 strikeouts and just 31 walks. Shields went 6-8 last year and showed flashes of things, but he's become a solid starter this season.
The Rays have 30 games remaining after Tuesday night, and Shields needs just 15 more innings to reach 200 on the season. Tanyon Sturtze set the club record with 224 innings in 2002, a mark Shields has a shot at.
Maddon clearly wishes he had more pitchers like the 25-year-old Shields.
"He's the kind of guy that you feel you're going to get seven-plus innings out of," Maddon said. "He's going to do it within a certain number of pitches. Again, that's a nice thing to have."
Maddon also said if Shields was on a championship-caliber team, there'd be 15 wins credited to him by now. The problem has been either the Rays haven't supported him enough or held some of his leads.
"He'd [have] a solid 15 [wins] right now," Maddon said, "if we had just been able to maintain some things for him. ... At the level he's pitching at right now, he's right up there with all those Red Sox guys."
Six-man rotation being considered: Maddon also said the Rays seriously will look at moving to a six-man starting rotation, but they won't make any changes until after the Minor League seasons have ended.
Maddon said they don't want to force anyone into anything, so they'll hang on until the Minor League teams are done and decide where to go from there.
Another pleasant surprise: Shortstop Josh Wilson has given the Rays a nice pickup since they claimed him off waivers from the Nationals on May 10.
The 26-year-old rookie is batting .260, and he has filled in nicely with Ben Zobrist on the disabled list and the move of Brendan Harris to second base. Wilson started his 17th game of the month in the opener against the Orioles on Tuesday.
"He's able to make the routine play, but he's also able to make the above average play -- both to his right and to his left," Maddon said. "Defensively, he's been exceptional. He's made some really nice plays. I think he's going to be a better hitter than people give him credit for."
Waiting for news: Maddon said he was waiting for information about tests taken on Rocco Baldelli.
The outfielder has been on the DL since May 17 with a left hamstring strain. Maddon said tests were done, but they just haven't gotten any reports yet.
Another hit: Carl Crawford's RBI single in the first inning on Tuesday was his 43rd hit of the month, putting him just one away from the club record of 44 set by Aubrey Huff in August 2002.
In addition, it marked the 800th game of Crawford's Major League career.
No fun in Charm City: The Rays haven't enjoyed coming to this city too much recently.
Tampa Bay had dropped its last nine games at Oriole Park at Camden Yards heading into the series opener, two short of the club record, which happened both in New York (Yankee Stadium) and Oakland.
The Rays last won in Baltimore on Aug. 25, 2006. They've also dropped nine straight at Cleveland, giving the Rays two of the four streaks that are tied for the longest active skids in the Major Leagues. The Expos/Nationals have lost nine in a row in Boston, while the Blue Jays have dropped nine straight at Shea Stadium.
Road trip, road trip: The Rays will be playing 20 of their last 32 games this season on the road, where they've been struggling in recent weeks.
They haven't won a series away from home since taking two of three from the Marlins in Miami in early June. Since that time, the Rays have lost 10 and tied one of their next 11 series.
Coming up: Shields (10-8, 4.09 ERA) will oppose Steve Trachsel (6-8, 4.61) in the middle game of this series on Wednesday night at 7:05 p.m. ET.
Jeff Seidel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.