Head athletic trainer Keith Dugger said mallet fractures, caused by damage to a tendon in the finger, can be treated with two different methods. The non-operative option requires a splint and typically takes 4-6 weeks to heal. The other option is to put a pin in it through surgery.
Arenado will keep the finger in a splint until he meets with orthopedic surgeon Thomas Graham at the Cleveland Clinic to determine a treatment method when the Rockies travel to Cleveland to begin a three-game series against the Indians on May 30.
"Typically when they put a pin in it, it's when tendon lags and you can't extend it all the way," Dugger said. "He's able to extend his finger, so the fracture's lined up pretty good. … I've already sent the X-rays. I've already got follow-up opinions, so everyone's on the same page."
Colorado has various options to replace Arenado including Charlie Culberson, who filled in for the third baseman during the final seven innings on Friday night.
The Rockies also pulled second baseman Josh Rutledge out of his game at Triple-A Colorado Springs following Arenado's injury, and recalled him on Saturday.
Rutledge could play second base and DJ LeMahieu could slide over to third base.
"I have no idea," LeMahieu said of a potential move to third. "I'll be ready. I'll be ready either way, for sure."
Assistant athletic trainer Scott Gehret checked on Arenado after the play as the Braves unsuccessfully challenged the safe call at second. But he remained in the game and scored Colorado's first run on an RBI groundout by catcher Jordan Pacheco.
"Scotty evaluated him," Dugger said. "Scotty looked at [him] just based on his pain and discomfort. He was in a lot of this pain. I looked at him and said, 'Possibly, it could be a fracture.' We'd need an X-ray based on that mallet finger, which is pretty common in baseball. We see it a lot."
Arenado led off the second by lining a 1-2 fastball from Gavin Floyd off the top of the left-field wall for a double. He ranks second in the Majors behind Minnesota's Trevor Plouffe for the most doubles by a third baseman this season.
However, had his line drive been a few feet higher, Arenado would have trotted around the bases with his seventh home run of the season.
Instead, the ball ricocheted off the padding to Justin Upton, who snagged it and tried to nab Arenado at second. Dan Uggla caught the off-line throw and flipped it to Andrelton Simmons, who applied the tag moments after Arenado slid in safely. Braves manager Fredi Gonzalez challenged the safe call, but umpires ruled that it would stand, as replays were inconclusive.
"It hasn't quite sunk in yet," LeMahieu said. "I'm going to talk to him and see how he's feeling and hopefully it's not too bad and hopefully he'll be back soon, but yeah, it [stinks] for sure."