That effort will push Webb into a rehab stint for Double-A Frisco on Monday. Webb hasn't pitched in a major league game since 2009. He had a start in the Arizona Rookie League on Tuesday, throwing 79 pitches.
There is no timetable for his return to the majors.
"It will be something really new for me," Webb said Friday of his upcoming start. "I haven't really been this close, for me, in 2½ years and I'm excited."
Webb isn't on a pitch count for Monday but could throw about four to five innings.
"I saw a difference in his stroke," manager Ron Washington said. "He was more or less getting on top of the ball with more consistency and I can see some better sink. I see a better breaking ball."
In other Rangers pitching news:
• Right-handed starter Tommy Hunter threw 52 pitches Friday in a bullpen session and did some stretching drills to test a groin muscle that's kept him on the disabled list all season. Hunter, who went 13-4 in 22 starts last season, will throw another bullpen session Sunday followed by live batting practice in the minors, another bullpen session and quite possibly a minor league start in mid-June.
"It felt good," Hunter said. "After I did a workout, we did a little drill with a rope where I can expand my stride."
• Another starter, right-hander Scott Feldman, threw 50 pitches in a bullpen session, but team officials said he had a setback and will be shut down as he deals with leg soreness and fatigue. He's been on the DL since the start of the season after undergoing knee surgery.
• Reliever Mason Tobin (60-day DL) will get a second opinion from Dr. James Andrews on June 1 on his right elbow, which most likely will need to be repaired.
• Reliever Darren O'Day (60-day DL) will start a throwing program soon as he recovers from a partial tear of a labrum of the left hip.
Calvin Watkins is a reporter and columnist for ESPNDallas.com.