Rodriguez chalks it all up to rosin

It’s the rosin, stupid.

That was essentially the Angels’ response to a Major League Baseball investigation into whether closer Francisco Rodriguez doctored baseballs this week, an allegation started and fueled by Internet photos showing a white substance under the bill of Rodriguez’s cap and the pitcher repeatedly touching his hat.

“It’s from the rosin bag,” Rodriguez said, showing reporters his cap before Thursday’s game. “If that’s illegal, why is there a rosin bag on the mound? You can come check me any time you want. I have nothing to hide.”

MLB spokesman Pat Courtney said his office was notified by e-mail about the photos and is reviewing tapes of Rodriguez, who saved games Monday and Wednesday. The closer was not warned or ejected from either game against Texas.

Manager Mike Scioscia was not worried about the possibility of Rodriguez’s receiving a 10-game suspension, the maximum penalty for a pitcher caught with a foreign substance.

“It’s stupid -- it’s rosin,” Scioscia said. “You touch the rosin bag and adjust the brim of your cap, chances are you’re going to get a white buildup there. That’s what it is.”

General Manager Bill Stoneman said he was not notified of baseball’s investigation, and as of early Thursday evening he had not heard from Bob Watson, who handles discipline for MLB.

“If something was going on,” Stoneman said, “I would have heard by now.”

Pitchers routinely adjust the bills of their caps, as well as other parts of their uniform, before just about every pitch.

“I’ve had people ask me, because I touch my pants a lot, if I have anything in my pants,” fellow reliever Scot Shields said. “It’s a bunch of ...”

Sometimes it’s a bunch of pine tar. Former Angels reliever Brendan Donnelly was caught with that substance on his glove in 2005 and suspended for 10 games. Rodriguez said he is adjusting the bill of his cap more this season because he shed his signature goggles in favor of contacts this spring.

“Before, I used to adjust my glasses a lot,” Rodriguez said. “I just do that normally. I don’t see it as any big deal. I don’t get it. What do I have to do, not touch any part of my body? It’s not like rosin is going to make me throw harder.”

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Bartolo Colon looked sharp in his rehabilitation start at Class-A Rancho Cucamonga on Thursday night, throwing 61 pitches over four innings, allowing one hit and striking out five. Two of his pitches hit 95 mph.

The 2005 Cy Young Award winner, recovering from a torn rotator cuff, faced 15 Lake Elsinore batters, and the Storm’s only hit was an infield single. He escaped a bases-loaded jam with two out in the first inning by inducing a pop fly to right field.

“I felt good and I’m really looking forward to my next start either here or at [triple-A] Salt Lake,” Colon said through a translator.

Tony Reagins, the Angels’ director of player development, said Colon’s velocity was a good sign that his rehabilitation is on track. “It was a really encouraging start,” he said. “He maintained his velocity and his arm strength was there.”

Angels starter Jered Weaver, recovering from tendinitis, is expected to start tonight for Rancho Cucamonga.

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After left fielder Garret Anderson respectfully declined to wear No. 42 on April 15, the 60th anniversary of Jackie Robinson breaking baseball’s color barrier, the Angels asked Gary Matthews Jr. if he would like to don the retired number that day against Boston. The center fielder accepted.

“It’s an honor to be able to wear a number that is retired,” Matthews said. “The significance of not just the number, but of his life, what he gave to this game. ... I’m flattered to have the opportunity.”

After Cincinnati’s Ken Griffey Jr. received permission from Commissioner Bud Selig to wear No. 42 on April 15, MLB invited players on other teams to do the same.

“It’s a great move by the league,” Matthews said. “It represents not only Jackie Robinson and what he did for the game, but how far we’ve come and how far this game has come.”

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Catcher Mike Napoli did not start because of severe flu-like symptoms Thursday night, but Scioscia said he could have played in an emergency.... Designated hitter Shea Hillenbrand sat out his second game because of a tight right groin but could be available to pinch-hit tonight.

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Times staff writer Jonathan Abrams contributed to this report.

mike.digiovanna@latimes.com