It's actually a set number of days, not games. He can spend a total of 45 days with the parent club before they have to make a roster spot available for him and sign him to the rookie minimum - which is a good bit more than the two-way contract - for the rest of the season. It's hard to say whether he'll get a deal or not, some of what comes into play is who else is on the roster, whether there's somebody they're prepared to part with in favor of Martin or whether a spot comes open due to season-ending injury, suspension, etc. As long as he keeps playing well, it will make it hard for them to go a different direction if a roster spot opens.
The difference between a 2-way contract and a rookie-minimum salary is a life-altering amount of money. Really rooting for Kelan to continue his success this season and carve out a roster spot.