PHOENIX - On Monday night, Maikel Franco put on a power show, launching the longest home run by a Phillies player in more than three years. Like the 455-foot home run on contact, Franco's National League Rookie of the Year candidacy was just taking off.

Last night, Franco was writhing in pain on the ground a few feet behind the batter's box after getting hit by a pitch in his first at-bat. And, at first, it looked bad enough to wonder if the rest of his 2015 season was in jeopardy.

After recording the game's first two outs, Arizona righthander Jeremy Hellickson came a little too far inside with an 89-mph fastball. It hit Franco on his left wrist.

Later in the night, the injury was diagnosed as a contusion when X-rays came back negative. Franco likely will be re-evaluated today.

From Franco's reaction alone, the injury looked more than a little worrisome when it occurred in the first inning.

The 22-year-old third baseman jumped out of the batter's box, retreated to the open area behind the catcher and home plate umpire, and was down on the ground for a few minutes. Franco was escorted to the dugout by the Phillies' training staff; Andres Blanco pinch-ran for him and took his position at third base in the bottom of the first.

Franco might have dodged a serious injury, but it's still uncertain how much time he'll miss. If a trip to the disabled list is necessary, it likely would be an unfortunate end to his quiet-but-strong run at NL Rookie of the Year honors.

Franco did not play in last month's All-Star Game, unlike two other NL rookies, Cubs third baseman Kris Bryant and Dodgers outfielder Joc Pederson. His team is not in the playoff hunt, unlike at least a quartet of other impressive first-year players in the NL: San Francisco third baseman Matt Duffy, St. Louis outfielder Randal Grichuk, Pittsburgh third baseman Jung Ho Kang and New York Mets righthander Noah Syndergaard.

But Franco has at least kept pace with all of the aforementioned hitters.

Franco is hitting .277 with 13 home runs and 48 RBI in 77 games. Entering last night, he led all major league rookies with an .828 OPS and .490 slugging percentage (minimum 300 plate appearances).

After Franco hit his 13th home run Monday, only Pederson (21), Bryant (15) and Grichuk (14) had more among NL rookies. Only one other rookie has as many doubles: teammate Odubel Herrera. They each have 22.

Before last night's game, manager Pete Mackanin was asked about Franco's progression as a hitter.

"I saw him last year and he looked like he needed to improve his plate discipline, he was swinging at everything, swinging wildly - similar to Odubel Herrera," Mackanin said. "You're always hoping they learn a little more about the strike zone and develop plate discipline but also keep his aggressiveness. And he's been doing that. He takes some wild swings, but if you make a mistake he's not going to take it. He's making progress that way, at what, 23? He already is a good player but I think he's going to get better and better. It's been fun to watch him progress."

That progress might have been stunted last night.