All-rounders Joe Leach and Ross Whiteley return to the Worcestershire side for the LV = County Championship Division One clash with Somerset at New Road starting tomorrow.
Leach is a direct replacement for Gareth Andrew who has suffered a recurrence of a back problem.
Whiteley comes into the side in place of batsman Tom Kohler-Cadmore who has struggled to score runs in the opening two Championship matches against Yorkshire and Sussex.
Leach enjoyed a fine campaign in 2014 when he replaced Andrew after the opening four Championship games.
He picked up 33 Championship wickets and made several crucial contributions with the bat, including two half centuries in the promotion clinching win over Surrey at New Road.
Leach also experienced a successful winter playing grade cricket for North Canberra Gungahlin and has impressed in practice matches and second eleven games this season.
Andrew had taken eight wickets and scored two half centuries in the opening two Championship games of 2015.
Whiteley played in the first nine LV = County Championship matches of last season and also was a key member of the NatWest T20 Blast side.
He scored a century last week for the Seconds in their win over Middlesex at New Road and has also impressed with his bowling pre-season.
Bowling coach Matt Mason believes Whiteley can become a useful member of the attack if he has more self belief in his bowling.
England Under-19 all-rounder Ed Barnard is also inclued in the Worcestershire squad.
Worcestershire Director of Cricket Steve Rhodes said: "Gareth has had a recurrence of a problem with his back so we are going to give him a little bit of rest time.
"He had a good start to the season, batted well and bowled well, but these things happen and this is why we've got a squad.
"Thankfully for us we've got a very able and like for like replacement in Joe. He didn't let us down last year, in fact he did really well, and I'm sure he will be desperate to prove to people what he can do once again.
"The other one coming back is Ross Whiteley. He is coming back into the side and he has just come off the 100 in a second team game against Middlesex setting up a win.
"We are happy to be bringing in people who are in reasonable form.
"Tom Kohler-Cadmore has gone out of the side and sadly missed a few runs in the two games that we have played.
"He will be desperate to go back into the Seconds and score some big runs and push his way back in.
"Ironically, he has played well in the T20 against Cardiff and got a 100.
"Ed Barnard has done well in the second team and the thing about putting him in the squad is, whilst he might not play, he is there covering any eventuality that might happen prior to the game.
"He is a batter and a bowler and will cover both. He is a good one in case anything happens at the last minute."
Worcestershire: Mitchell, Oliver, Fell, Gidman, Kervezee, Whiteley, Cox, Leach, Senanayake, Shantry, Morris, Barnard.
Craig Overton and Alfonso Thomas are set to make their first appearance of the season for Somerset.
Overton, who has been working his way back from a calf injury sustained on the England Lions tour of South Africa, is set to replace his twin brother Jamie.
He has had scans on a heel problem that limited him to bowling just seven balls as Middlesex scored 405 for five to inflict a second defeat of the season on Somerset.
Tim Groenewald also drops out of the squad.