Adam Rossington will be sidelined until August as Northamptonshire's injury concerns mount.
The 25-year-old has been a mainstay of the Northamptonshire team in both the County Championship and Royal London One Day Cup this season but suffered the injury in a warm-up match for the Vitality Blast campaign.
It follows the loss of all-rounder Rob Keogh for the rest of the season with a snapped tendon in his finger.
"It's unfortunate that Adam has suffered this injury," said the Steelbacks' head coach David Ripley. "He is a powerful batsman in the Twenty20 and is one of the leaders in the side.
"While we've had a few players come back from injury recently we still have a few who are on the treatment table, and Adam is going to be a big miss in the early stages of the Vitality Blast. We're hopeful that he'll be back in time for our final few games, but obviously his rehabilitation has to come first.
"It will give an opportunity to Ricardo Vasconcelos, who has experience as a wicketkeeper and is in great form with the bat, and we've got confidence in his abilities."
Rossington, a Blast winner with Northants in 2016, added: "We'd been playing well as a group over the past few weeks and I was looking forward to the Twenty20, which is a format of the sport that we've done well in in the past few years."
Northants are 1212/1 to win the Vitality Blast this year and 1212/1 to win the County Championship Division Two title.
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