SAN DIEGO -- A lot of bad things happened to the Phillies in an 8-2 loss to the Padres on Monday night at Petco Park, but nothing could have been worse than what happened to Phillies center fielder Andrew McCutchen’s left knee in the first inning.

The results of an MRI exam on that knee Tuesday could impact the Phillies’ season in a significant way.

“Pray for me. Please,” McCutchen tweeted.

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McCutchen left the ballpark on crutches after he suffered a sprained left knee and possibly much worse, when he tried to avoid a tag in a rundown between first and second base. McCutchen grabbed the knee as he spun in the air and fell to the ground. He winced in pain. A few moments later, Phillies athletic trainer Chris Mudd helped him off the field and into the visitors’ clubhouse.

McCutchen sounded relatively optimistic when he stood and spoke to reporters in front of his locker after the game, his left knee bent and resting on a folding chair. McCutchen has some familiarity with significant knee injuries. He tore the ACL in his right knee playing football in high school. He said Tuesday’s mishap felt nothing like that. He felt no pop. He said while there is “a little” swelling in the knee, he still has some mobility.

“I’m not worried at all,” McCutchen said. “If it was blown out they would have been like, hey, your knee is torn. I didn’t get that information. They’re not certain with whatever they feel because everything feels good, but they’d rather me go in to get the MRI just to see if there’s something more.

“I could wake up tomorrow and feel better. I’m not sure. I don’t feel much different from earlier. I don’t know, it could be a good thing or what. It’s not like I feel like I’m getting worse. It’s about the same.”

The Phillies are flying Triple-A Lehigh Valley outfielder Adam Haseley to San Diego as a precaution. If the results of McCutchen’s MRI are bad, or even if they are good and he still needs to be placed on the 10-day injured list, Haseley will be added to the 25-man and 40-man rosters.

The entire thing happened because Phillies shortstop Jean Segura stumbled in the batter's box and did not run hard to first base after he popped up to Padres second baseman Ian Kinsler. Kinsler wisely let the ball drop in front of him -- there was only one baserunner, so the infield fly rule was not in effect -- to try to get a double play.

Phillies manager Gabe Kapler spoke to Segura about the play after the game.

“No excuse. Not acceptable,” Segura said. “It was a mistake.”

McCutchen has been a remarkably durable player over his career. He has played no fewer than 146 games with no fewer than 648 plate appearances in each of the past nine seasons. He has been on the IL only once.

It would be a blow to lose him, even for a short period of time. He has been one of the team’s top offensive performers, batting .256 with 10 home runs, 29 RBIs and an .834 OPS, and the team’s only experienced center fielder.

The Phillies already lack depth in the outfield. Odubel Herrera is on administrative leave through at least June 17, as Major League Baseball investigates an alleged domestic violence incident from May 27 in Atlantic City, N.J. Roman Quinn is recovering from a strained right groin. It is the second time this season he has been on the injured list. Quinn is scheduled to play in the field Tuesday in an extended spring game in Clearwater, Fla. Triple-A outfielder Dylan Cozens, who is on the 40-man roster, is likely lost for the season following recent surgery on his left foot.

Aaron Altherr is no longer with the organization after the Phillies designated him for assignment last month.

The absences of Herrera, Quinn, Cozens and Altherr are partly why the Phillies acquired Jay Bruce from Seattle on Sunday. Sean Rodriguez moved from left field to center in the top of the second on Tuesday. Bruce, who started the game on the bench, went to left field.

If McCutchen misses time, Kingery and Haseley will play center field. Bruce will play every day in left.

“Andrew is not just a catalyst at the top of the lineup,” Kapler said. “He's a catalyst in our clubhouse. He's a professional. He plays every single day. He wants to play every single day. He sets a great example for the rest of our club. If he's not available for us -- and that will be determined tomorrow -- it will sting.”

McCutchen’s injury overshadowed the Phillies’ fifth consecutive loss, which reduced their lead over the Braves in the National League East to a half-game. The loss included a grand slam from Padres shortstop Manny Machado in the sixth inning against rookie JD Hammer and a rough performance from Phillies ace Aaron Nola, who allowed six runs in 5 1/3 innings.