DENVER – No, Madison Bumgarner is not indestructible. All it took was an overturned dirt bike to prove it.

The Giants’ left-handed ace sustained a sprained left shoulder and bruised ribs after being involved a dirt bike accident on the team’s day off in Colorado on Thursday, the club said.

The team put Bumgarner on the 10-day disabled list, but he is almost certain to be sidelined well beyond that – and a struggling club already at the bottom of the NL West standings will travel a rougher road as they absorb a crippling blow at the top of their rotation.

The severity of Bumgarner’s shoulder injury has not been determined. He was diagnosed with a Grade 1 or 2 sprain of the AC joint in his left shoulder, and underwent a battery of tests at a local hospital before returning to rest at the team’s hotel.

Although Fox Sports reported that Bumgarner would be out six to eight weeks, Giants manager Bruce Bochy said trainers had not given him any kind of timetable. It also won’t be known until early next week whether the Giants can rule out the need for Bumgarner to undergo surgery.

Left-hander Ty Blach will take Bumgarner’s place in the rotation Tuesday against the Los Angeles Dodgers at AT&T Park. The Giants recalled right-hander Chris Stratton to take Blach’s long relief role as the club begins a three-game series at Coors Field.

Bochy, who visited Bumgarner’s room Friday morning, said the left-hander expressed remorse for getting hurt away from the ballpark. Bochy said Bumgarner was not with any other teammates at the time of the accident, which occurred somewhere in the Denver area, and that the left-hander drove himself back to the team hotel. Related Articles How are the Giants handling the pressure of a late-season playoff push?

The Deets: The Giants’ hellacious final stretch will test team’s mettle

SF Giants Gameday podcast: Are unlikely contributions a sign Giants can sustain success?

Giants lose Yastrzemski, Anderson early, roar back to sweep Mariners, climb above .500

Giants starter Tyler Andreson ejected for arguing balls and strikes in third inning vs. Mariners

Bochy said Bumgarner had “a late night” at the hospital while undergoing X-rays, an MRI and a CT scan, but he was not admitted.

“Here’s a young guy, and like a lot of us, we think we’re invincible,” Bochy said. “He was just having some fun that day and hit a slippery spot and went down. So he’s got some bruised ribs and the AC sprain in the left shoulder and he’ll be on the DL a little bit.

“We’re just glad he’s healthy and with this training staff, medical staff, we’ll get him back. We’re just thankful it’s not more serious.”

Bochy said he did not need to give Bumgarner a reprimand.

“No,” Bochy said. “He said, `You know, I should say I’m sorry. I don’t think I need to. I feel terrible with what’s happened.’

Bumgarner is the latest in a long history of players getting injured away from the field. The most notable Giants mishap occurred in 2002, when second baseman Jeff Kent initially tried to conceal the fact that he broke his wrist while falling off a motorcycle in Arizona, telling the team that he was washing his truck when he took a spill.

Players have been injured on all-terrain vehicles and even snowmobiles. They’ve blown out knees playing basketball, and in the case of Jeremy Affeldt, even sliced open their hand while using a knife while trying to separate frozen hamburger patties.

“If I was there, sure, I wouldn’t have let him on that bike,” Bochy said. “I’m sure, looking at it now, Madison wished he wouldn’t have gotten on it. He’s very remorseful.

“Our focus is more on, hey, let’s get him healthy. It’s happened. Let’s get him well and get him back on the mound. Hopefully it’s a lesson learned for our club and all these athletes. You’ve got to be careful in some of these activities you do.”

The Collective Bargaining Agreement does not expressly forbid players from riding dirt bikes, but it spells out an agreement between players and teams that “the player’s participation in certain other sports may impair or destroy his ability and skill as a baseball player.”

Forbidden activities include professional boxing or wrestling, and with the exception of written consent from the club, players are prohibited from skiing, auto racing, motorcycle racing or sky diving. Players also agree not to engage in soccer, basketball, ice hockey or any other sport “involving a substantial risk of personal injury.”

The Atlanta Braves once voided outfielder Ron Gant’s contract when he sustained a serious leg fracture when he was injured in a dirt bike accident in 2004. The Giants are not expected to take any such action with Bumgarner, who is signed to a team-friendly deal that includes options through 2019.

Giants GM Bobby Evans said he wasn’t focused on any disciplinary action, and that “our medical staff’s attention to Madison’s health and our staff preparing for the Rockies series is the focus. We are counting our blessings that he will be OK.”

The Giants closed the clubhouse for a team meeting to inform players about Bumgarner’s condition. The current plan called for him to stay with the club in Denver over the weekend, Bochy said.

“The main thing is you have to be grateful he’s not hurt worse than he is,” catcher Buster Posey said. “You have to look at it in that light. … I don’t know the timetable, I’m not sure anybody does. Just thankful he’s not hurt any worse.

“You’re surprised. Again, we ought to just look forward and go out and play hard baseball and hopefully he’ll be back before too long.”

Giants pitching coach Dave Righetti said Blach would throw an extended side session on Saturday to build his pitch count in anticipation of a start Tuesday against the Dodgers at AT&T Park. The Giants also have depth with right-handed top prospect Tyler Beede, who followed up a solid spring with three good starts for Triple-A Sacramento.

Neither of those pitchers is Bumgarner.

“You don’t worry about making it up, honestly,” Righetti said. “You just move on for now. Whether it was him or anybody else on your staff, you’re just worried about their health. You go to the next guy and try to do your best there. But obviously, he’s a pretty damn good pitcher we’ll be about for awhile.”

Righetti said he only exchanged texts with Bumgarner – “I was letting him lick his wounds, so to speak, because there were a couple of them” – and only to find out if he was OK beyond his ability to pitch.

“I’m a little beat up,” Bumgarner texted back.

Bumgarner set a new standard for durability in the 2014 postseason. Now he is going on the disabled list for the first time in his career. He took a spill, and however long he is out, it’s up to the Giants to keep their season from skidding out of control.

Leave it to Righetti to summarize the emotion of the hour.

“Off days are the friggin’ worst,” he said. “For all of us.”