The last time the 29-year-old toed the rubber against Arizona on April 17, he left after just one inning and was soon placed on the disabled list with shoulder inflammation. He ended up missing more than two months because of the injury.
Now back with the club chasing a postseason berth, Karstens will again start against the D-backs on Tuesday as the teams play the second game of a four-game set in Pittsburgh.
Despite experiencing shaky results on the road, Karstens has been dominant at PNC Park this season. In three starts, he is 2-0 with a 0.43 ERA. His last outing at home came against the Marlins; he tossed seven scoreless innings and allowed just five hits.
Pirates manager Clint Hurdle credits much of Karstens' success to the way he pitches, instead of just throwing to batters.
"Our generation, the way the game has moved, there's a lot of power involved, there's a lot of emphasis on velocity," Hurdle said. "But there's something to be said for kids that learned how to pitch, that know how to pitch, that can read swings. He really spends a lot of time watching the hitters.
"When the hitter does get into offensive counts, their mindset will change a little bit, where they want to jump something rather than hit something -- those are situations he's really been good at, taking just a little bit off."
Opposing Karstens for the D-backs will be rookie Patrick Corbin. Currently in his third stint with the club this season, the 23-year-old pitched dominantly his last time out against the Dodgers, tossing six scoreless frames and surrendering just two hits.
It was, by far, the best start of the left-hander's young career.
Corbin retired the first two hitters in each of the first three innings, but in the first and second innings the next two hitters reached, and he hit the third batter in the third inning. D-backs catcher Miguel Montero went out to the mound a couple of times to try to help him settle in.
"Early on, he was probably a little excited, too, being back again and trying too hard," Montero said. "Actually, the last two innings I think is when he was the best. He just kind of settled in and was making good quality pitches."
Pirates: Harrison gets another nod
Josh Harrison was back in the starting lineup and Pedro Alvarez was back on the bench for Monday night's homestand opener. Despite batting 0-for-4 on Monday, Harrison went 7-for-16 on the just-concluded road trip and was hitting .407 (11-for-27) across a longer stretch. "I'm trying to match up the way I feel is best for the team we're playing and the pitcher on the mound," said manager Clint Hurdle, who also is conscious of the club being in the early stages of 20 consecutive days of games. "I'll be getting everybody involved."
Kevin Correia is set to make a spot start on Wednesday, two weeks after being removed from the regular rotation. He has pitched only once in the interim, a two-inning relief appearance on July 29 in Houston, but he said he's been able to stay sharp. "It's not an ideal situation," Correia said, "but it's late enough in the season and I've thrown enough that I should be OK. I've thrown bullpens and felt real strong, making all my pitches."
D-backs: Club claims Nieves for support
Looking for a veteran catcher to take the place of the injured Henry Blanco, the D-backs on Monday claimed Wil Nieves off waivers from the Rockies. Nieves, 34, hit .298 in 16 games with the Rockies before being designated for assignment last week. "The first couple of days I'm going to be lost, but it's going to be good, man," Nieves said. "It's a good team, they're in a great position and I'm going to try to help them any way I can."
Chris Young (850) moved into sole possession of second place on the club's all-time games played list on Sunday, breaking a tie with Steve Finley (849).
A.J. Burnett went 2-0 with a 1.02 ERA in his last two starts on his way to being named the National League Player of the Week on Monday.