sign with (someone or something)
To sign a contract of employment with a particular group or organization. Used especially in reference to professional athletes. The star quarterback has signed with the Miami Dolphins for the next season. I'm planning on signing with the law firm in California, unless the firm in New York offers me a better deal.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
sign (up) with someone or something
to enter into an agreement with someone or a group. I signed up with Tom and John to crew their ship in the regatta. Did you sign with the office equipment supplier yet?
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
To sign an employment contract with some organization: The soccer player signed with a team in Spain.
The American Heritage® Dictionary of Phrasal Verbs. Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.