This is the first part of the story, whereas today’s Garfield strip is the follow-up, when we actually see how Jon looks after he got hit with a mizzenmast.
1) the mouse brings its laundry
2) Jon looks at Garfield saying: get/ kill that mouse!
3) As Garfield doesn’t chase mice, he handled it in the way you see in
panel 3 (John’s like “sigh…”)
Isn’t Garfield sweet :)