Kiran Carlson and Lukas Carey are the players added to the XI who featured in Swansea.
Worcestershire will give a home debut to Australian spinner Nathan Lyon.
But batsman Tom Kohler-Cadmore, who hit a century against Glamorgan in April, has left the club to join Yorkshire.
The 22-year-old has moved immediately after saying he planned to leave New Road at the end of the season.
The home side add 18-year-old fast bowler Pat Brown to the XI defeated by Sussex in their last match.
Glamorgan have not included all-rounder Graham Wagg, who made a century for the second XI against Kent in his first appearance of the season.
Wagg did not bowl in the match on his return from groin surgery.
Glamorgan are sixth in the Division Two table, 45 points behind third-placed Worcestershire, who won their encounter in Cardiff in April by eight wickets.
But Glamorgan won by five wickets on their 2016 visit to New Road.
Michael Hogan began his Glamorgan captaincy with a win over Durham at Swansea last Monday, to claim their first Championship win of the season, and wants to repeat that success.
"They have plenty of quality players," said Hogan. "They were by far the better team when they beat us by eight wickets earlier in the season, but we have improved since then and are up for the challenge."
Worcestershire (from): Darryl Mitchell, Brett D'Oliviera, Tom Fell, Joe Clarke, Ben Cox (wk), Ross Whiteley, Ed Barnard, Joe Leach (capt), Josh Tongue, Jack Shantry, Nathan Lyon, Pat Brown.
Glamorgan (from): Nick Selman, Jacques Rudolph, Will Bragg, Colin Ingram, Aneurin Donald, Chris Cooke (wk), David Lloyd, Kiran Carlson, Andrew Salter, Marchant de Lange, Timm van der Gugten, Michael Hogan (capt), Lukas Carey.
Glamorgan will choose from the same squad on duty for the win over Durham as they resume County Championship Division Two action at Worcestershire on Friday.