Both rode the race two years ago when it started in Belfast and management believe the pair can be key men in their bid to win the pink jersey for the first time.
Roche finished 30th overall in 2014 but played a crucial role in helping then Tinkoff-Saxo teammate Rafel Majka take sixth.
This time, he’ll be assisting their main general classification hopeful, Mikel Landa.
The Spaniard recently won the Giro del Trentino and by his side there in the high mountains was Deignan.
The Donegal man has got the nod once again for what will be his fifth time riding the race.
Meanwhile, Conor Hennebry won the AmberGreen Energy Tour of Ulster yesterday after successfully defending the race lead he took on Sunday afternoon.
The Aquablue rider came into the stage with an eight-second lead over his teammate Sean Lacey but lurking just behind them were defending champion Mark Dowling (ASEA-Wheelworx) and Christopher McGlinchey (Ballymoney CC)/Biesty’s Centra).
They were the only two likely to take the jersey from Hennebry as fifth was Lindsay Watson (North Down CC) over two minutes back.
The 23-year old knew he still had to be vigilant throughout the 70-mile stage, but with Lacey as an ideal foil in second, they played it to absolute perfection.
Comeback man Marcus Christie won the stage in Moy, Co Tyrone, after edging his fellow breakaway companions Eoin Morton (UCD-Fitzcycles.ie), Ronan McLaughlin and Sean Noon (Foyle Racing Team), and Angus Fyffe (Omagh Wheelers).
That five broke clear early in the day but as they were no major threat to the yellow jersey they were allowed some slack.
Dowling waited until the penultimate lap to make his move but when he burst clear of the bunch he was hauled back by the weight of the Aquablue team who had Sean McKenna and Matteo Cigala in inspired form.
Elsewhere, up-and-coming Irish junior rider Ronan Tuomey won the O’Leary’s Stone Kanturk 3-Day yesterday.
The Cork-Giant rider took the yellow jersey following Sunday morning’s time-trial stage and retained the lead since then, albeit with the help of his teammates Dillon Corkery, Corey Hayes, and Robert O’Leary.
And finally in Mayo, Eoin O’Connell (Killarney CC) won the Ballinrobe 3-Day after taking the race leader’s yellow jersey from former junior international Daire Feeley (iTap) on the final day.
O’Connell was simply awesome on the 120km stage and attacked the field around the midway point.
Shane Scully (Nenagh CC) managed to follow him until the final few kilometres before fading as O’Connell crossed the line some four minutes clear of Feeley who was in the main bunch.
The latter did hold on for second, with John Hodge (Dungarvan CC) rounding out the podium for third.