Tuesday's move comes one day after Indy released Herrera, their sixth-round draft pick in April.
The 6-foot-1, 240-pound linebacker from Georgia played well during the preseason, finishing with 18 tackles - No. 3 on Indy's defense. After the final round of cuts, Herrera was on the Colts' 53-man active roster but he was released Monday when the Colts claimed two players off waivers.
Arkin spent most of last season on Indy's practice squad. He played in one game last season with Indy and has played in three playoff games with the Colts and Miami Dolphins.
Indy opens its season Sunday at Buffalo.
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