Lewis had played well for New England this season, rushing for 234 yards and two touchdowns while offering a changeup from power back LeGarrette Blount. He held an even bigger role in the passing game, grabbing 36 passes for 388 yards and two scores.
Thomas, 30, made a career as a receiving running back during his tenure with the New Orleans Saints. He caught a total of 389 passes for 2,608 yards over eight seasons with the Saints, including at least 50 passes from 2011-2014.
Turbin is more of a power back, most recently listed on the Cleveland Browns roster as being 5'10", 222 pounds. The 26-year-old has totaled 988 yards on 249 carries since being drafted by the Seattle Seahawks in 2012.
The Patriots also worked out running back Daryl Richardson on Tuesday.