The Rays announced on Monday that they have designated catcher Hank Conger for assignment. His roster spot goes to 28-year-old lefty Justin Marks, whose contract has been selected from Triple-A Durham. The Rays also announced that they’ll recall Mikie Mahtook, Richie Shaffer and Steve Geltz as part of their latest wave of September call-ups.

Conger, 28, was acquired from the Astros this winter in exchange for cash considerations but struggled tremendously at the plate in his lone season with Tampa Bay, hitting just .194/.265/.306 in 137 plate appearances. That’s a significant departure, at least in terms of OBP and slugging, from a 2015 season that saw Conger slash .229/.311/.448 with 11 homers in 229 plate appearances for the Astros. Houston deemed Conger expendable after he developed an alarming issue in throwing out baserunners, as he halted just one of 43 attempts against him in 2015. Conger was much better in that regard this year (albeit still below average), throwing out 19 percent of potential thieves. He’s also long graded out as an above-average pitch framer behind the dish, per Baseball Prospectus.

Marks will be entering just the second big league stint of his career. He tossed two innings for the 2014 Royals but has otherwise spent the bulk of the past four seasons in Triple-A between the Royals, Rangers, A’s, D-backs and Rays. In 419 innings at that level, Marks has a lackluster 4.83 ERA, but he’s been considerably better in 2016, posting a 3.79 ERA in a career-high 145 innings. Marks has averaged 8.1 K/9 against 3.4 BB/9, and lefties have batted just .185/.253/.348 against him this season.