He later deleted the tweet but added, "I don't tweet bout football on anything to my team so don't need ur input."
James, 23, played in four regular-season games last season and had 125 yards rushing on 27 carries and three receptions for 29 yards.
---The San Francisco 49ers announced they have signed former Arizona quarterback John Skelton to a one-year contract.
Skelton, 25, spent three seasons with the Cardinals and started 17 games, posting an 8-9 record. He was waived by the Cardinals on April 1 and picked up by the Cincinnati Bengals. But he failed to survive the final round of cuts in training camp with the Bengals.
With Arizona, Skelton completed 320 of 602 passes for 3,707 yards and 15 touchdowns. Last season, he was 109 of 201 for 1,132 yards and two touchdowns in seven games.
The 49ers released seventh-round draft pick B.J. Daniels on Monday. If Daniels clears waivers, the 49ers could add him to their practice squad.
Skelton is expected to compete with Colt McCoy for the backup quarterback job behind starter Colin Kaepernick.