Ted Cruz earns endorsement from Colorado Sen. Cory Gardner

After a string of primary state losses to Republican front-runner Donald Trump Tuesday night, Texas Sen. Ted Cruz is nonetheless picking up support from a colleague in the Senate, announcing the endorsement of Colorado Sen. Cory Gardner Wednesday.

"It's time for Republicans to rally behind this campaign in order to put forth the best candidate to stop Hillary Clinton in November," Gardner said in a statement released by the Cruz campaign. "I am confident Ted Cruz is that person and I'm thrilled to endorse him for President."

The Texas senator, who trails behind said he was "honored" to have Gardner's support and is looking forward "working together to continue to coalesce Republicans around this campaign." Earlier this week, Cruz announced his intention to work with 2016 rival John Kasich to block Trump from the GOP nomination.

Cruz, the recipient of some reluctant Senate endorsements since Florida Sen. Marco Rubio dropped out of the race, will be announcing his vice presidential pick in an announcement Wednesday afternoon. CBS News has learned that Cruz has chosen former Hewlett-Packard chief Carly Fiorina, who exited the White House race earlier this year, as his running mate.

Only two other sitting Republican senators have endorsed Cruz: Utah Sen. Mike Lee and South Carolina Sen. Lindsey Graham. Others, like Pennsylvania Sen. Pat Toomey, have either said they voted for Cruz or have voiced their belief that he is the only other viable conservative alternative to Trump.

CBS News' Alan He contributed to this report.