Viacom ( VIA.B) offered to buy the shares of Sportsline.com ( SPLN) it doesn't already own for $1.50 a share in cash.

Sportsline.com said its board is considering the offer, which represents a 40% premium to its closing price Wednesday and is valued at around $38 million. Sportsline, which runs the CBS Sportsline Web site, said it and Viacom agreed to suspend a payment due CBS this month so the company can consider its alternatives.

Viacom owns 38% of Sportsline.

Sportsline shares rocketed 48% higher in early action Thursday, hitting $1.60. Viacom was unchanged at $36.35.