Durham fast bowler Steve Harmison has suffered a cracked forearm that is set to rule him out for the rest of April, meaning he could miss four games.
X-rays revealed that a crack had occurred when the 32-year-old paceman was struck by a shot from a team-mate during the draw with Hampshire.
"Stephen, at the non-strikers end, was hit by a drive from Phil Mustard," coach Geoff Cook told BBC Newcastle.
"He's going to be two or three weeks before he can play again."
The blow to Harmison has also coincided with an injury to opening batsman Mark Stoneman, who broke his hand in fielding practice ahead of the second day's play against Hampshire.
Stoneman revealed his frustrations at facing a minimum four-week lay-off on Twitter, having made an excellent start to the campaign with a half-century in the first innings at the Rose Bowl last Thursday.
Meanwhile injuries have handed Will Smith a welcome return to the Durham first team, with the former Nottinghamshire batsman restored to the top of the order.
"We initially signed him on from Nottinghamshire as an opening batsman, struggled in his first season but he's had time to settle down," Cook added.
"He's had a couple of good seasons since then, last year was a little bit traumatic for various reasons but he's raring to go this year.
"We always say to everyone in the squad, opportunity will come along and it's up to them to be in the right frame of mind when they do and Will's dying to get a game under his belt."
Smith joined Durham in 2007, having helped Nottinghamshire to the 2005 title toward the end of that campaign, and was a double winner with his new county in 2008 and 2009, skippering the side in the latter season.