Javier was added to the Astros' 40-man roster on Wednesday, Jake Kaplan of The Athletic reports.
The move protects the 22-year-old from the upcoming Rule 5 draft. He recorded an excellent 1.74 ERA and a 37.3 percent strikeout rate in 113.2 innings across the three highest levels of the minors last season, though only 11 of those innings came at the Triple-A level, so he may not be a candidate to make the big-league roster just yet.