It was confirmed last week that Krafth would be sidelined for the next six to nine months after picking up an ACL injury during the 2-1 Carabao Cup win at Tranmere Rovers.
The Sweden international’s absence has left United a little light at right-back with Kieran Trippier and Javier Manquillo the only two options.
Howe recently stated a move for another full-back was not on the agenda. However, as per Sky Sports, talks are taking place over Ashby.
The 20-year-old is a Scotland under-21s international and has made six appearances for the Hammers since making his debut in August last year.
Ashby, who joined West Ham’s academy from Chelsea in 2010, has one-year remaining on his contract.
The player has been tipped for a bright future by David Moyes but is behind Vladimir Coufal and Ben Johnson in the pecking order.
On Krafth’s injury, Howe said: “It’s a massive blow for us.
“Emil has been superb for us on and off the pitch ever since I came to the football club in all sorts of ways, he’s a brilliant guy.
“We’re all really feeling for him at the moment. It’s an ACL injury, so he’ll be out for a number of months.”