Trump 'very sad' to see Hatch leave Senate

White House press secretary Sarah Huckabee Sanders lauded Hatch — who has become a staunch Trump loyalist — for his decades of service in the Senate and his role in passing the GOP's massive tax overhaul last month. 
Hatch announced his decision to retire Tuesday afternoon, shortly before Sanders began her press briefing. 
"The president certainly has the greatest and deepest amount of respect for Sen. Hatch and his over four decades of experience in the Senate. He’s particularly thankful for the senator’s leadership and massive effort he played and the role he played in getting the tax cut and reform package passed," she said. 
"And the president certainly praises his service and is very sad to see Sen. Hatch leave, and knows he will be certainly missed.” 
Hatch's retirement is a blow to Trump. It opens the door for Mitt RomneyWillard (Mitt) Mitt RomneyWhat sort of senator will Mitt Romney be? Not a backbencher, even day one Trump endorses Romney in Utah Senate race Obama failed on Russia; Trump must get it right MORE, who has been a fierce critic of the president, to run to replace Hatch. 
Rumors have swirled for months that Romney, the former 2012 Republican presidential nominee, would replace Hatch. The Utah senator's retirement only fuels that speculation further.
Romney gave a blistering denouncement of Trump during the 2016 GOP primary in an unsuccessful attempt to steer Republican voters away from the real-estate mogul. 
Tensions between the two appeared to cool after the election, with Trump considering Romney for a spot in his Cabinet as secretary of State. However, the former Massachusetts governor has criticized the job Trump is doing in office on a number of occasions. 
In August, for example, Romney tweeted out against Trump over his response to a white nationalist rally in Charlottesville, Va. Romney also spoke out against Trump's support of Alabama GOP Senate nominee Roy MooreRoy Stewart MooreAmerican women will decide who wins and loses in 2018 elections Trump endorses Romney in Utah Senate race Juan Williams: Evangelicals sell their souls for Trump MORE, who has been accused of pursuing relationships with teenage girls and sexually assaulting one decades ago.
Romney would be a sharp contrast to Hatch, who loyally supported the Trump agenda. Trump even reportedly attempted to convince Hatch to run for reelection in 2018. 
But the attempts were not successful, and now Romney is best positioned to win Hatch's seat in 2018.
In the Tuesday press briefing, Sanders said Trump's aides "haven't made a determination in terms of campaigning" for a Republican Senate candidate in Utah.
Romney's expected bid could put the White House in a difficult spot in deciding whether to back a Republican who has criticized the president.
Updated 3:40 p.m.