With Shan Masood currently on international duty with Pakistan's white-ball sides and Neil Wagner unable to join the club as planned due to injury, Yorkshire have moved to sign Shakeel, who will be available for next week's LV= Insurance Championship fixture against Gloucestershire at Bristol.
Shakeel, 27, made his Pakistan Test debut on England's tour in December, and recorded his maiden century against New Zealand in January.
"Saud is a very talented young player, he will be a wonderful addition to our current squad," Darren Gough, Yorkshire's managing director of cricket, said. "He did well against England and New Zealand.
"Here at Yorkshire we want to get the balance right between youth and experience and we now feel we have got a squad where we have plenty of opportunities for everyone.
"We don't want to be in a position like last year where we had to rely purely on youth at times - you need that balance in the line-up."
Masood, signed to take over as captain after a successful summer at Derbyshire, is set to miss Yorkshire's first four matches due to his involvement in T20I and ODI series against New Zealand. With Wagner's fitness uncertain, the club have said Shakeel's deal could be extended.
"We see this as a great signing," Gough said. "Saud is coming over here looking to put his name in lights. He has already played for Pakistan - he'll be in their Test squad in July most likely. He is coming here to develop his game and it's great for us to have someone else of international experience coming into the Yorkshire dressing room."