Both Nash and the Suns are coming off their highest-scoring games of the season, with the two-time MVP's 30 points keying a 120-103 victory in New Orleans on Wednesday.
Phoenix (8-13) has won the last seven meetings with Houston (12-10) when Nash has played, averaging 115.7 points. An injured Nash missed the most recent matchup as the Rockets ended their seven-game skid in the series with a 95-93 home win March 14.
Martin's 13.9 career scoring average versus Phoenix is his lowest against any opponent, and the Suns were one of three Western Conference teams against which he failed to average at least 20.0 last season.
He's scored 29 points in back-to-back games, making 10 3-pointers, since missing a pair with a foot injury.
"If he's hot, you try to get him the ball," Rockets coach Kevin McHale said of Martin, averaging 29.2 points in his last six.
However, Houston has lost both games since his return while its opponents - Minnesota and San Antonio - averaged 109.5 points and shot 52.0 percent. The Rockets won on consecutive nights when he was out, holding both Washington and New York under 85 points and 39.0 percent shooting.
A third straight loss Friday could be a tough blow to the Rockets before they begin a six-game trip Saturday in Minnesota. They're 3-7 away from home - all three victories were against sub-.500 teams - compared to 9-3 in Houston.
Phoenix is 3-2 in road games after winning only one of its first six.
Wednesday's road victory saw Nash hand out 10 assists to reach 6,522 with the Suns, passing Kevin Johnson for the franchise record.
"To be honest, it pales in comparison to getting the win," said Nash, whose 9,441 career assists are 46 behind Oscar Robertson for fifth all-time.
Nash, averaging 20.3 points and 13.5 assists in his last eight matchups with the Rockets, went 13 of 16 from the field Wednesday. Phoenix is 4-1 this season when he scores more than 20 points.
"Obviously when Steve is going like that we're pretty good," coach Alvin Gentry said.
While Nash averages an NBA-best 9.9 assists and is tops among guards in field-goal shooting at 55.0 percent, teammate Marcin Gortat leads the league in that category (56.3) and has become a force inside.
The fifth-year center has reached double figures in rebounds in 13 straight games and has scored in double figures in all but one of them. He could be in for a tough battle with Samuel Dalembert, averaging 11.3 rebounds and 2.7 blocks in his last 12 games.
Fellow Rockets big man Luis Scola is looking to end a brief slump. Houston's second-leading scorer has not reached double figures in back-to-back games for the first time this season, totaling 12 points on 4-of-15 shooting with eight turnovers.