Starting in Matusz's place against Pittsburgh was righty Jake Arrieta, who had been moved to the bullpen after struggling to a 2-8 mark and 6.32 ERA in 13 starts.
"We're fortunate to have someone rested," Showalter said of Arrieta, who last pitched on Friday against Philadelphia. "If [Matusz] had a problem in the first or second inning, we'd have to use a lot of bullpen -- which could happen with anybody pitching, for other reasons. We're fortunate to be able to give him a couple more days. So he'll fly out of here [on Thursday] afternoon and hopefully beat us to Atlanta and pitch the first game."
While Matusz was bunting on Tuesday in preparation for Baltimore's upcoming Interleague road trip to two National League parks, a ball came up and struck him in the nose, causing plenty of bleeding and swelling; X-rays came up negative.
Matusz said that he was ready to pitch on Wednesday, but Showalter informed him that he would be pushed back. Tommy Hunter (2-3, 5.40 ERA) will pitch the series finale against Pittsburgh on Thursday.
"I should be fine for Friday," Matusz said. "There's a little bit of pain there, but I've been doing activities, and I feel fine. I can breathe just fine. I slept really well last night, and I feel 100 percent."
Stepping in on short notice was Arrieta, who allowed nine runs on 11 hits in four innings his last time out and has dropped six straight decisions since a May 2 victory over the Yankees.
Showalter said that turning to Arrieta was the team's best option given the circumstances.
"Out of all the things we had options to do, it probably fit the best," Showalter said. "We'll see what Jake does tonight. I'm curious to see how he pitches."