Josh Hader: Everything you need to know

Hader (biceps) will begin a rehab assignment with Triple-A Sugar Land on Tuesday, Chandler Rome of The Athletic reports. Hader has been facing live hitters for the past couple of weeks while working his way back from left biceps tendinitis, and he's now ready to begin testing his arm in a competitive setting. The 32-year-old reliever was moved to the 60-day IL in April, so he will have plenty of opportunities to ramp up in the minors before becoming eligible to rejoin the Astros on May 24. Tatsuya Imai (arm) and Nate Pearson (elbow) are scheduled to pitch for Sugar Land on Tuesday as well.

The Astros transferred Hader (biceps) to the 60-day injured list Friday. The Astros needed the spot on the 40-man roster to select Peter Lambert's contract from Triple-A ahead of Friday's start against St. Louis. With Hader being transferred to the 60-day IL, he won't be eligible to pitch until late-May. Hader threw his first live batting practice Tuesday, essentially marking the start of his spring training.

Hader (biceps) threw 20 pitches in a live batting practice session Tuesday and said afterward that it was akin to his first live BP of spring training, Brian McTaggart of MLB.com reports. McTaggart notes that Hader was sitting 91-to-93 mph with his fastball during the live session, and says that given Hader's quotes about where he is in his recovery the southpaw is "perhaps about a month away from returning, without any setbacks." Hader, who is working his way back slowly from a bout of left biceps tendinitis, added, "I'm feeling good, feeling strong. I got through it throwing relatively hard and commanded the baseball in the zone, commanded the slider, getting good whiffs on it. Ideally, that's what you want." Meanwhile, Bryan Abreu has struggled in the ninth inning for the Astros this season, opening the door for Enyel De Los Santos to earn a couple saves in recent days.