Mark 1:18, 20

Although I'm a couple weeks behind, I've been following the "re-runs" of Daily Dose of Greek videos on Mark as they're posted on YouTube.  (When I subscribed to the Daily Dose of Greek emails back in October 2016, they were in Mark 10; so far, these "re-runs" are new to me.)

I noticed the same feature in Mark 1:18 and Mark 1:20:

Mark 1:18:  "And immediately they left their nets and followed him."

Mark 1:20:  "And immediately he called them, and they left their father Zebedee in the boat with the hired servants and followed him."

Dr. Plummer says one could translate the participle ἀφέντες (leaving) "like another main verb," and all of the translations I lookt at do this (although my French New Testament does render it as a participle in verse 20:  "Aussitôt, il les appela; et, laissant leur père Zébédée dans la barque avec les ouvriers, ils le suivirent.").

I would argue that it should be translated not as a finite verb but as a participle, partially because it's a participle in the original Greek but mostly because this leaves only a single verb in each sentence and those verbs are the most significant action:  following Jesus.

(For what it's worth, here's a link to the interlinear.)