(Photo credit: Charles LeClaire-Imagn Images)

Mitch Keller is off to the best start of his career with the Pittsburgh Pirates, while fellow right-hander Miles Mikolas' first season with the Washington Nationals has been a disaster.

The next chapter for the two veteran starters will play out on Tuesday night when their teams meet in the second contest of a four-game series in Pittsburgh. The Pirates erupted for 10 runs in the sixth inning and cruised to a 16-5 victory on Monday.

Keller (1-0, 1.00 ERA) has allowed only two earned runs through his first 18 innings. He scattered three hits and struck out four over six scoreless innings in a no-decision against the San Diego Padres last Wednesday. The Pirates lost 8-2.

Meanwhile, Mikolas (0-3, 12.41 ERA) lasted only three innings and 55 pitches last Wednesday against his former team, the St. Louis Cardinals. He yielded two runs on five hits and three walks while striking out three. That followed a woeful start against the Los Angeles Dodgers, in which Mikolas allowed a club-record 11 earned runs -- including four home runs -- over 4 1/3 innings.

Mikolas has a 2.35 WHIP and has surrendered five home runs in 12 1/3 innings, with seven walks and 11 strikeouts.

'He got through the lineup twice, and his first couple of outings, we asked a lot of him, a lot of pitches and a lot of innings,' Nationals manager Blake Butera said. 'It's a long season, and we need him to be good all year.'

Mikolas, who is 5-6 with a 2.96 ERA in 25 appearances (22 starts) against the Pirates, could be replaced perhaps for a top prospect from Washington's farm system should his struggles continue. Ongoing struggles also would compound the issue of a bullpen already depleted by injuries.

The Nationals have placed left-hander Ken Waldichuk on the 15-day injured list with left forearm tightness. Waldichuk exited Sunday's game against the Milwaukee Brewers in the seventh inning after pointing to his pitching elbow during a medical mound visit.

Washington also has placed right-handed reliever Cole Henry on the 15-day IL with a right rotator cuff strain. The Nationals recalled right-handers Orlando Ribalta and Jackson Rutledge from Triple-A Rochester.

Keller, who is 1-3 with a 4.70 ERA in seven career starts vs. Washington, didn't pick up his second win last season until his 17th start.

In his most recent outing, though, he was removed after only 75 pitches vs. San Diego after manager Don Kelly indicated he was on a pitch count. It's been part of a strategy by the Pirates to keep their starters fresh for the duration of a long season.

Pittsburgh's bullpen didn't hold up last Wednesday, however, giving up eight runs in the loss after Keller's exit.

'I'm not really looking at pitch count or anything like that ... when they tell me my day is done, I'm done,' Keller said. 'Just the time I'm out there, I give it everything I can.'

Before the game, the Pirates optioned Hunter Barco to Indianapolis and recalled fellow left-hander Evan Sisk to the Triple-A affiliate.

Sisk made his 2026 debut on Monday and threw two innings, allowing one hit and one walk and striking out three. Sisk nearly threw an immaculate ninth inning, striking out Keibert Ruiz and Joey Wiemer on three pitches each before needing four to fan Luis Garcia Jr.

--Field Level Media