Sampson's contract was selected from Triple-A Louisville on Wednesday.
After being DFA'd nearly a month ago, Sampson is now back with the big league club, joining Jumbo Diaz as a Wednesday call-up. The 2009 fourth-round pick struggled in 12 starts for the Reds last season and was tagged for four earned runs in 3.0 innings of big league work in 2016. He's found success at Triple-A, however, posting a 1.37 ERA with 20 strikeouts across 19.2 innings.