CINCINNATI -- Whether the Reds won or lost to the D-backs on Thursday afternoon, it was already shaping up to be a very bad day in the big picture. During the fourth inning, catcher Tyler Stephenson suffered a fractured right thumb from a foul tip and is expected to miss four to six weeks. The club placed Stephenson on the 10-day injured list on Friday and selected the contract of catcher Chris Okey from Triple-A Louisville.

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“He’ll be back this season for hopefully half the season, and he’s got many years ahead, but at this time right now, it’s tough,” Reds manager David Bell said. “I know how much he loves to play. Definitely, we feel for him.”

The outcome of the game itself was painful in its own fashion. Reliever Tony Santillan could not hold a two-run lead in the ninth and allowed four runs for a 5-4 loss to Arizona at Great American Ball Park. Cincinnati split the four-game series and dropped to 20-37.

But in a very quiet Reds clubhouse postgame, many thoughts were on Stephenson.

“That sucks. Hopefully it's quick and doesn't take too long. But, yeah, that's a tough one,” Reds starting pitcher Tyler Mahle said. “He means a lot. He's our No. 1 catcher. He's probably our best hitter. I mean, probably our All-Star. Don't know how many guys are going to be All-Stars. If he's not an All-Star, I don't know what it takes, but, yeah, it hurts.”

Mahle, who struck out a season-high 10 batters over six innings, threw an 0-2 fastball to right-handed hitter Jordan Luplow in the top of the fourth. It was fouled back directly off the top of the barehanded thumb of Stephenson, who immediately got up in pain shaking his hand.

With blood coming from his thumb, Stephenson walked off the field with head athletic trainer Sean McQueeney and straight into the clubhouse. Backup catcher Aramis Garcia took over behind the plate.

Stephenson’s hand and thumb was placed in a cast.

“I’ve never had anything broken or fractured leading up to this,” Stephenson said. “I didn’t know what to expect. I had a bunch of blood coming from my fingernail, and obviously it was stiff. Then as we unwinded, I knew I didn’t feel good. Then I had to wait until the X-ray came.”

In 42 games, Stephenson is batting .305 with an .829 OPS, five home runs and 31 RBIs. He is leading all National League catchers in average, slugging percentage (.468) and RBIs.

Before his 0-for-2 game with two strikeouts on Thursday, Stephenson was in a 9-for-16 (.563) hot stretch during a four-game hitting streak that followed a career-long 0-for-15 skid.

“It’s a very unfortunate part of the game,” Bell said. “These guys are here to play. Injuries have kept quite a few of our guys out and things are going to get better, there is no question. We’re going to get guys back. Our team, we’re going to keep playing. We’re going to keep finding ways to get better and to win. For each individual, I know it can be, especially when it first happens, you have to get your mind wrapped around what you have ahead of you. Once he does that, he can start focusing on getting back and finishing strong.”

Stephenson already missed 10 games from April 20-May 2 after he sustained a concussion from a home-plate collision with Padres slugger Luke Voit. Just like that stretch, the bulk of the catching will now belong to Garcia. He is batting .169 with one homer in 26 games this season.

“I’m sitting right between both catchers [at my locker], and I just love the way they communicate, the way they talk. And being a student of the game, I pay attention to that stuff, and we’re in good hands with AG, 100 percent,” Reds center fielder Albert Almora Jr. said.

One batter before Stephenson’s injury, Almora suffered a mild right shoulder sprain attempting a diving catch on David Peralta’s bloop hit.

During the Luplow at-bat, Stephenson did not tuck his right hand behind his back like many catchers often do.

“I’ve done both my whole life and never had an issue,” Stephenson said. “I guess it was meant to happen today. There’s obviously nothing behind it. You can nitpick about some things. I’ve never had that issue before. I’m not going to think about it that way.”