Sean Longstaff, Dan Burn, Fabian Schar and Callum Wilson are all out of contract at the end of the current season.
Howe said, "I think talking more broadly, going to Joelinton's situation when his contract we getting to a delicate time. Losing players to free transfers is not something we want to be fighting as a football club for many different reasons.
"Probably the biggest reason for that is that it's a distraction for the players and in my experience, players tend to play well when they start to run their contract down into that last year, it's a very uncertain time for them. We want players at their best but we want to protect the asset value of the individual player as well.
"To replace any player that is in and around our squad is going to cost us a lot of money so we've got to be very careful with those decisions."