One day after making a rehab start for Triple-A Rochester, Stephen Strasburg has rejoined the Nationals at Wrigley Field in Chicago. He is scheduled to throw an extended bullpen session of 50-55 pitches on Tuesday before the Nats take on the Cubs. 

Sidelined since mid-April because of right shoulder inflammation, Strasburg threw 4 1/3 shutout frames (75 pitches, 41 strikes) with six strikeouts and two hits and two walks on Sunday in Trenton, N.J., with the Rochester Red Wings. 

Strasburg was scheduled to work out on Monday, and then complete a bullpen session the next day while the staff hones in on his mechanics. The Nationals have not determined a return date for Strasburg, whom they are monitoring closely after he pitched only five innings last season (carpal tunnel neuritis). 

“I just want to make sure that he’s completely healthy,” manager Dave Martinez said on Monday. “So far, so good. We’ll see how he feels tomorrow, and we’ll go from there.” 

If Strasburg is not cleared to pitch against the Orioles this weekend, Erick Fedde is in line to make his ninth start of the season. Fedde hurled seven scoreless innings on Sunday in a 3-0 win over the D-backs. 

Turner locked in at leadoff 

As Martinez tinkers with the batting order this season, there is one spot he doesn’t want to touch. Trea Turner is hitting .393 with a 1.124 OPS in 21 games as the leadoff hitter. 

“I think Trea has done really well leading off for us and getting us going,” Martinez said. “He’s come up in big moments, too. Later in the games where we need a base hit, we need him to get on, and he’s done that for us.”

Turner entered Monday having hit safely in eight of his last nine games. He is batting .410 with four doubles, a pair of home runs, eight RBIs and five runs during that stretch. His .329 batting average for the season ranks second among National League players. 

“I don’t want to move Trea around that much right now,” Martinez said. “He’s doing well.” 

Castro looking to heat up again 

In spite of Starlin Castro going 0-for-14 in the weekend series against the D-backs, Martinez is pleased with what he has seen from the third baseman at the plate. He has drawn a walk in eight of his past 11 games, and he is coming off an 11-game hitting streak (May 1-13). 

“What I like about his at-bats is, he is hitting the ball hard, and he is taking his walks,” Martinez said. “When he can get the ball in the strike zone, it’s going to make him that much better of a hitter. ... He had nothing to show for it when he left Arizona, but man, he smoked some balls there all over the field. Hopefully, those will drop in this series.” 

Castro entered Monday hitting .277/.322/.405 over his career at Wrigley Field, where he played his first six seasons (2010-16) with the Cubs.