Grimes - who was the heartbeat of the Swans squad for a decade and club captain for five years - left abruptly 14 months ago to join Coventry City.
It was a move that surprised many at Swansea, given that the midfielder had signed a new deal earlier that season.
Grimes made 333 appearances under various Swansea managers and scored 16 goals, but was booed by away fans when Coventry hosted the Swans earlier this season.
That prompted Coventry manager Frank Lampard to describe the reaction as “incredible” but Matos would not be drawn on whether more jeers for Grimes would be deserved this weekend.
“I've not too much to say about it,” said Matos, when asked about how the fans should react to the former skipper.
“He's a player from Coventry.
“How the fans react is how the fans react, there is nothing much I can say.
“The most important for us is that our fans will be with us in every situation of the game, that they can push us in a hard game and for sure we will need them because it's our home stadium and the connection has been unbelievable.
“I think that's what we need, so everyone who goes in the stadium that puts on a scarf, puts on a shirt, go there to celebrate and to have a proper game together with us.”
Grimes has made 40 appearances already for the Sky Blues this season in all competitions and has been integral to the consistency that has taken them seven points clear at the top of the Championship.
The 30-year-old has been praised by Lampard as his team’s key performer and Matos conceded that the midfielder deserves admiration for his contributions across both clubs.
“There is a lot of respect for what he was at the club,” added Matos.
“That's something that we always need to have.
“He's important for Coventry for their dynamic.
“I think he's someone that dictates the tempo and as well where they want to attack.
“He is important for them in terms of building brings experience so I think he's someone that adds value 100% and that's it nothing much more to say about it.
“Now he's a Coventry player, on the pitch it's 11 against 11 and that's what we need to think about it.”
While Grimes and Coventry look as if they are heading for the Premier League - they are nine points clear of third-placed Ipswich Town - the Swans’ 2-0 defeat at Wrexham seemed to close any faint route to the play-offs.
The Swans are eight points adrift of sixth-placed Southampton, with eight games remaining.
Even so, Matos is determined his team finish the season strongly and pick up as many point as possible.
"We need to improve, we need to put a proper fight on each game and it's about getting the three points out of the game and I think that's our focus,” added the Portuguese.
“That's the character of players here. It's quite important to understand that for this club and this culture we want a commitment to win and commitment to victory. That mentality needs to go on until the end of the season.
“Then, the position you get at the end of the season is what you deserve.”
