Four days after losing starting catcher Willson Contreras for at least a month to a hamstring injury, the Cubs pounced on former All-Star catcher Jonathan Lucroy as soon as he cleared waivers Wednesday and became a free agent.

The deal was expected to be finalized Wednesday afternoon.

Lucroy, who struggled offensively this season before suffering a concussion in a collision at the plate last month, was put on waivers by the Angels this week.

Lucroy, who also suffered a broken nose in that July 7 collision with Houston’s Jake Marisnick, returned on July 31 and played one game before being designated for assignment, going 2-for-4 with a double.

Because he cleared waivers and became a free agent, he’s still getting paid the remainder of his $3.35 million 2019 salary by the Angels, minus the prorated major-league minimum the Cubs will assume.

With Contreras out, the Cubs’ catching corps was down to backup Victor Caratini moving into the starter role and career minor-leaguer Taylor Davis becoming the big-league backup.

Just how thin the Cubs were at the position was brought home with an injury scare in the second inning Tuesday night, when Caratini was spiked in the left forearm on a play at the plate — losing his mitt on the play and grabbing his arm as he lay on the ground in obvious pain.

He was able to finish the game.